diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list-experimental.js b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list-experimental.js
index 6ba5db9206..c2dff1d393 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list-experimental.js
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list-experimental.js
@@ -26,7 +26,7 @@ import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mix
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-messages-list-experimental_html.js';
 import {KeyboardShortcutBehavior} from '../../../behaviors/keyboard-shortcut-behavior/keyboard-shortcut-behavior.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 import {MessageTag} from '../../../constants/constants.js';
 import {appContext} from '../../../services/app-context.js';
 
@@ -219,8 +219,8 @@ class GrMessagesListExperimental extends mixinBehaviors( [
         combinedMessages = combinedMessages.concat(messages.slice(mi));
         break;
       }
-      mDate = mDate || util.parseDate(messages[mi].date);
-      rDate = rDate || util.parseDate(reviewerUpdates[ri].date);
+      mDate = mDate || parseDate(messages[mi].date);
+      rDate = rDate || parseDate(reviewerUpdates[ri].date);
       if (rDate < mDate) {
         combinedMessages.push(reviewerUpdates[ri++]);
         rDate = null;
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
index d1e6fced57..adf9fd35ca 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.js
@@ -25,7 +25,7 @@ import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mix
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-messages-list_html.js';
 import {KeyboardShortcutBehavior} from '../../../behaviors/keyboard-shortcut-behavior/keyboard-shortcut-behavior.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 import {appContext} from '../../../services/app-context.js';
 
 const MAX_INITIAL_SHOWN_MESSAGES = 20;
@@ -191,8 +191,8 @@ class GrMessagesList extends mixinBehaviors( [
         result = result.concat(messages.slice(mi));
         break;
       }
-      mDate = mDate || util.parseDate(messages[mi].date);
-      rDate = rDate || util.parseDate(reviewerUpdates[ri].date);
+      mDate = mDate || parseDate(messages[mi].date);
+      rDate = rDate || parseDate(reviewerUpdates[ri].date);
       if (rDate < mDate) {
         result.push(reviewerUpdates[ri++]);
         rDate = null;
@@ -303,14 +303,14 @@ class GrMessagesList extends mixinBehaviors( [
     const messages = this.messages || [];
     const index = message._index;
     const authorId = message.author && message.author._account_id;
-    const mDate = util.parseDate(message.date).getTime();
+    const mDate = parseDate(message.date).getTime();
     // NB: Messages array has oldest messages first.
     let nextMDate;
     if (index > 0) {
       for (let i = index - 1; i >= 0; i--) {
         if (messages[i] && messages[i].author &&
             messages[i].author._account_id === authorId) {
-          nextMDate = util.parseDate(messages[i].date).getTime();
+          nextMDate = parseDate(messages[i].date).getTime();
           break;
         }
       }
@@ -324,7 +324,7 @@ class GrMessagesList extends mixinBehaviors( [
             fileComments[i].author._account_id !== authorId) {
           continue;
         }
-        const cDate = util.parseDate(fileComments[i].updated).getTime();
+        const cDate = parseDate(fileComments[i].updated).getTime();
         if (cDate <= mDate) {
           if (nextMDate && cDate <= nextMDate) {
             continue;
diff --git a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.js b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.js
index 5a076a5a78..5ff48af14b 100644
--- a/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.js
+++ b/polygerrit-ui/app/elements/change/gr-thread-list/gr-thread-list.js
@@ -22,7 +22,7 @@ import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-l
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin.js';
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-thread-list_html.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 
 import {NO_THREADS_MSG} from '../../../constants/messages.js';
 
@@ -163,8 +163,8 @@ class GrThreadList extends GestureEventListeners(
         return c1.thread.line - c2.thread.line;
       }
 
-      const c1Date = c1.__date || util.parseDate(c1.updated);
-      const c2Date = c2.__date || util.parseDate(c2.updated);
+      const c1Date = c1.__date || parseDate(c1.updated);
+      const c2Date = c2.__date || parseDate(c2.updated);
       const dateCompare = c2Date - c1Date;
       if (dateCompare === 0 && (!c1.id || !c1.id.localeCompare)) {
         return 0;
diff --git a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.js b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.js
index cc4122d297..040b0bd4ae 100644
--- a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.js
+++ b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.js
@@ -21,7 +21,7 @@ import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mix
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-comment-api_html.js';
 import {PatchSetBehavior} from '../../../behaviors/gr-patch-set-behavior/gr-patch-set-behavior.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 
 const PARENT = 'PARENT';
 
@@ -470,7 +470,7 @@ class ChangeComments {
         .sort(
             (c1, c2) => {
               const dateDiff =
-                  util.parseDate(c1.updated) - util.parseDate(c2.updated);
+                  parseDate(c1.updated) - parseDate(c2.updated);
               if (dateDiff) {
                 return dateDiff;
               }
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
index 684c4a8c5e..b367265ed3 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.js
@@ -27,7 +27,7 @@ import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-diff-host_html.js';
 import {PatchSetBehavior} from '../../../behaviors/gr-patch-set-behavior/gr-patch-set-behavior.js';
 import {GrDiffBuilder} from '../gr-diff-builder/gr-diff-builder.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {DiffSide, rangesEqual} from '../gr-diff/gr-diff-utils.js';
 import {appContext} from '../../../services/app-context.js';
@@ -667,7 +667,7 @@ class GrDiffHost extends mixinBehaviors( [
     return comments.slice(0).sort((a, b) => {
       if (b.__draft && !a.__draft ) { return -1; }
       if (a.__draft && !b.__draft ) { return 1; }
-      return util.parseDate(a.updated) - util.parseDate(b.updated);
+      return parseDate(a.updated) - parseDate(b.updated);
     });
   }
 
diff --git a/polygerrit-ui/app/elements/gr-app-global-var-init.js b/polygerrit-ui/app/elements/gr-app-global-var-init.js
index f0a9131d81..2c166f53f1 100644
--- a/polygerrit-ui/app/elements/gr-app-global-var-init.js
+++ b/polygerrit-ui/app/elements/gr-app-global-var-init.js
@@ -48,7 +48,6 @@ import {GrRangeNormalizer} from './diff/gr-diff-highlight/gr-range-normalizer.js
 import {GrCountStringFormatter} from './shared/gr-count-string-formatter/gr-count-string-formatter.js';
 import {GrReviewerSuggestionsProvider, SUGGESTIONS_PROVIDERS_USERS_TYPES} from '../scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider.js';
 import {util} from '../scripts/util.js';
-import moment from 'moment/src/moment.js';
 import page from 'page/page.mjs';
 import {Auth} from './shared/gr-rest-api-interface/gr-auth.js';
 import {EventEmitter} from './shared/gr-event-interface/gr-event-interface.js';
@@ -103,7 +102,6 @@ export function initGlobalVariables() {
   window.GrCountStringFormatter = GrCountStringFormatter;
   window.GrReviewerSuggestionsProvider = GrReviewerSuggestionsProvider;
   window.util = util;
-  window.moment = moment;
   window.page = page;
   window.Auth = Auth;
   window.EventEmitter = EventEmitter;
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js
index 52e81c505c..8c10a113d8 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread.js
@@ -26,7 +26,7 @@ import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-comment-thread_html.js';
 import {PathListBehavior} from '../../../behaviors/gr-path-list-behavior/gr-path-list-behavior.js';
 import {KeyboardShortcutBehavior} from '../../../behaviors/keyboard-shortcut-behavior/keyboard-shortcut-behavior.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
 import {appContext} from '../../../services/app-context.js';
 
@@ -307,8 +307,8 @@ class GrCommentThread extends mixinBehaviors( [
 
   _sortedComments(comments) {
     return comments.slice().sort((c1, c2) => {
-      const c1Date = c1.__date || util.parseDate(c1.updated);
-      const c2Date = c2.__date || util.parseDate(c2.updated);
+      const c1Date = c1.__date || parseDate(c1.updated);
+      const c2Date = c2.__date || parseDate(c2.updated);
       const dateCompare = c1Date - c2Date;
       // Ensure drafts are at the end. There should only be one but in edge
       // cases could be more. In the unlikely event two drafts are being
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js
index aefb72f07e..5335edeab3 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter.js
@@ -22,13 +22,7 @@ import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mix
 import {PolymerElement} from '@polymer/polymer/polymer-element.js';
 import {htmlTemplate} from './gr-date-formatter_html.js';
 import {TooltipBehavior} from '../../../behaviors/gr-tooltip-behavior/gr-tooltip-behavior.js';
-import {util} from '../../../scripts/util.js';
-import moment from 'moment/src/moment.js';
-
-const Duration = {
-  HOUR: 1000 * 60 * 60,
-  DAY: 1000 * 60 * 60 * 24,
-};
+import {parseDate, fromNow, isValidDate, isWithinDay, isWithinHalfYear, formatDate, utcOffsetString} from '../../../utils/date-util.js';
 
 const TimeFormats = {
   TIME_12: 'h:mm A', // 2:14 PM
@@ -106,6 +100,10 @@ class GrDateFormatter extends mixinBehaviors( [
     };
   }
 
+  constructor() {
+    super();
+  }
+
   /** @override */
   attached() {
     super.attached();
@@ -113,7 +111,7 @@ class GrDateFormatter extends mixinBehaviors( [
   }
 
   _getUtcOffsetString() {
-    return ' UTC' + moment().format('Z');
+    return utcOffsetString();
   }
 
   _loadPreferences() {
@@ -190,50 +188,28 @@ class GrDateFormatter extends mixinBehaviors( [
     return this.$.restAPI.getPreferences();
   }
 
-  /**
-   * Return true if date is within 24 hours and on the same day.
-   */
-  _isWithinDay(now, date) {
-    const diff = -date.diff(now);
-    return diff < Duration.DAY && date.day() === now.getDay();
-  }
-
-  /**
-   * Returns true if date is from one to six months.
-   */
-  _isWithinHalfYear(now, date) {
-    const diff = -date.diff(now);
-    return (date.day() !== now.getDay() || diff >= Duration.DAY) &&
-      diff < 180 * Duration.DAY;
-  }
-
   _computeDateStr(
       dateStr, timeFormat, dateFormat, relative, showDateAndTime
   ) {
     if (!dateStr || !timeFormat || !dateFormat) { return ''; }
-    const date = moment(util.parseDate(dateStr));
-    if (!date.isValid()) { return ''; }
+    const date = parseDate(dateStr);
+    if (!isValidDate(date)) { return ''; }
     if (relative) {
-      const dateFromNow = date.fromNow();
-      if (dateFromNow === 'a few seconds ago') {
-        return 'just now';
-      } else {
-        return dateFromNow;
-      }
+      return fromNow(date);
     }
     const now = new Date();
     let format = dateFormat.full;
-    if (this._isWithinDay(now, date)) {
+    if (isWithinDay(now, date)) {
       format = timeFormat;
     } else {
-      if (this._isWithinHalfYear(now, date)) {
+      if (isWithinHalfYear(now, date)) {
         format = dateFormat.short;
       }
       if (this.showDateAndTime) {
         format = `${format} ${timeFormat}`;
       }
     }
-    return date.format(format);
+    return formatDate(date, format);
   }
 
   _timeToSecondsFormat(timeFormat) {
@@ -253,11 +229,11 @@ class GrDateFormatter extends mixinBehaviors( [
     }
 
     if (!dateStr) { return ''; }
-    const date = moment(util.parseDate(dateStr));
-    if (!date.isValid()) { return ''; }
+    const date = parseDate(dateStr);
+    if (!isValidDate(date)) { return ''; }
     let format = dateFormat.full + ', ';
     format += this._timeToSecondsFormat(timeFormat);
-    return date.format(format) + this._getUtcOffsetString();
+    return formatDate(date, format) + this._getUtcOffsetString();
   }
 }
 
diff --git a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_test.html b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_test.html
index 7169ef27c3..589a1576a0 100644
--- a/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-date-formatter/gr-date-formatter_test.html
@@ -34,7 +34,7 @@ limitations under the License.
 <script type="module">
 import '../../../test/common-test-setup.js';
 import './gr-date-formatter.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 suite('gr-date-formatter tests', () => {
   let element;
   let sandbox;
@@ -51,7 +51,7 @@ suite('gr-date-formatter tests', () => {
    * Parse server-formatter date and normalize into current timezone.
    */
   function normalizedDate(dateStr) {
-    const d = util.parseDate(dateStr);
+    const d = parseDate(dateStr);
     d.setMinutes(d.getMinutes() + d.getTimezoneOffset());
     return d;
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
index 207aa29b76..2d951d40f5 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.js
@@ -29,7 +29,7 @@ import {RESTClientBehavior} from '../../../behaviors/rest-client-behavior/rest-c
 import {GrEtagDecorator} from './gr-etag-decorator.js';
 import {SiteBasedCache, FetchPromisesCache, GrRestApiHelper} from './gr-rest-apis/gr-rest-api-helper.js';
 import {GrReviewerUpdatesParser} from './gr-reviewer-updates-parser.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 import {authService} from './gr-auth.js';
 
 const DiffViewMode = {
@@ -2075,7 +2075,7 @@ class GrRestApiInterface extends mixinBehaviors( [
   _setRanges(comments) {
     comments = comments || [];
     comments.sort(
-        (a, b) => util.parseDate(a.updated) - util.parseDate(b.updated)
+        (a, b) => parseDate(a.updated) - parseDate(b.updated)
     );
     for (const comment of comments) {
       this._setRange(comments, comment);
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.js b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.js
index c2d364aa3b..ed474d8704 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.js
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.js
@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 import {MessageTag} from '../../../constants/constants.js';
 
 /** @constructor */
@@ -106,8 +106,8 @@ GrReviewerUpdatesParser.prototype._groupUpdates = function() {
     if (!this._batch) {
       this._batch = this._startBatch(update);
     }
-    const updateDate = util.parseDate(update.updated).getTime();
-    const batchUpdateDate = util.parseDate(this._batch.date).getTime();
+    const updateDate = parseDate(update.updated).getTime();
+    const batchUpdateDate = parseDate(this._batch.date).getTime();
     const reviewerId = update.reviewer._account_id.toString();
     if (updateDate - batchUpdateDate >
         GrReviewerUpdatesParser.REVIEWER_UPDATE_THRESHOLD_MILLIS ||
@@ -206,14 +206,14 @@ GrReviewerUpdatesParser.prototype._advanceUpdates = function() {
   const updates = this.result.reviewer_updates;
   const messages = this.result.messages;
   messages.forEach((message, index) => {
-    const messageDate = util.parseDate(message.date).getTime();
+    const messageDate = parseDate(message.date).getTime();
     const nextMessageDate = index === messages.length - 1 ? null :
-      util.parseDate(messages[index + 1].date).getTime();
+      parseDate(messages[index + 1].date).getTime();
     for (const update of updates) {
-      const date = util.parseDate(update.date).getTime();
+      const date = parseDate(update.date).getTime();
       if (date >= messageDate &&
           (!nextMessageDate || date < nextMessageDate)) {
-        const timestamp = util.parseDate(update.date).getTime() -
+        const timestamp = parseDate(update.date).getTime() -
             GrReviewerUpdatesParser.MESSAGE_REVIEWERS_THRESHOLD_MILLIS;
         update.date = new Date(timestamp)
             .toISOString()
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser_test.html b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser_test.html
index f2ccfb7fb8..fa54d6b030 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser_test.html
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser_test.html
@@ -27,7 +27,7 @@ limitations under the License.
 <script type="module">
 import '../../../test/common-test-setup.js';
 import {GrReviewerUpdatesParser} from './gr-reviewer-updates-parser.js';
-import {util} from '../../../scripts/util.js';
+import {parseDate} from '../../../utils/date-util.js';
 
 suite('gr-reviewer-updates-parser tests', () => {
   let sandbox;
@@ -253,7 +253,7 @@ suite('gr-reviewer-updates-parser tests', () => {
   });
 
   test('_advanceUpdates', () => {
-    const T0 = util.parseDate('2017-02-17 19:04:18.000000000').getTime();
+    const T0 = parseDate('2017-02-17 19:04:18.000000000').getTime();
     const tplus = delta => new Date(T0 + delta)
         .toISOString()
         .replace('T', ' ')
@@ -297,8 +297,8 @@ suite('gr-reviewer-updates-parser tests', () => {
     instance = new GrReviewerUpdatesParser(change);
     instance._advanceUpdates();
     const updates = instance.result.reviewer_updates;
-    assert.isBelow(util.parseDate(updates[0].date).getTime(), T0);
-    assert.isBelow(util.parseDate(updates[1].date).getTime(), T0);
+    assert.isBelow(parseDate(updates[0].date).getTime(), T0);
+    assert.isBelow(parseDate(updates[1].date).getTime(), T0);
     assert.equal(updates[2].date, tplus(100));
     assert.equal(updates[3].date, tplus(500));
   });
diff --git a/polygerrit-ui/app/node_modules_licenses/licenses.ts b/polygerrit-ui/app/node_modules_licenses/licenses.ts
index fe07569b4a..4c259cd6c7 100644
--- a/polygerrit-ui/app/node_modules_licenses/licenses.ts
+++ b/polygerrit-ui/app/node_modules_licenses/licenses.ts
@@ -272,14 +272,6 @@ const packages: PackageInfo[] = [
     name: "isarray",
     license: SharedLicenses.IsArray
   },
-  {
-    name: "moment",
-    license: {
-      name: "moment",
-      type: LicenseTypes.Mit,
-      packageLicenseFile: "LICENSE"
-    }
-  },
   {
     name: "page",
     license: SharedLicenses.Page
diff --git a/polygerrit-ui/app/package.json b/polygerrit-ui/app/package.json
index 59894930c2..a9668c3043 100644
--- a/polygerrit-ui/app/package.json
+++ b/polygerrit-ui/app/package.json
@@ -26,7 +26,6 @@
     "@webcomponents/shadycss": "^1.9.2",
     "@webcomponents/webcomponentsjs": "^1.3.3",
     "es6-promise": "^3.3.1",
-    "moment": "^2.24.0",
     "page": "^1.11.5",
     "polymer-bridges": "file:../../polymer-bridges/",
     "ba-linkify": "file:../../lib/ba-linkify/src/",
diff --git a/polygerrit-ui/app/scripts/util.js b/polygerrit-ui/app/scripts/util.js
index d4baf292c0..0103bf23e9 100644
--- a/polygerrit-ui/app/scripts/util.js
+++ b/polygerrit-ui/app/scripts/util.js
@@ -29,14 +29,6 @@ function getPathFromNode(el) {
 // TODO (dmfilippov): Each function must be exported separately. According to
 // the code style guide, a namespacing is not allowed.
 export const util = {
-  parseDate(dateStr) {
-    // Timestamps are given in UTC and have the format
-    // "'yyyy-mm-dd hh:mm:ss.fffffffff'" where "'ffffffffff'" represents
-    // nanoseconds.
-    // Munge the date into an ISO 8061 format and parse that.
-    return new Date(dateStr.replace(' ', 'T') + 'Z');
-  },
-
   getCookie(name) {
     const key = name + '=';
     const cookies = document.cookie.split(';');
diff --git a/polygerrit-ui/app/types/custom-externs.js b/polygerrit-ui/app/types/custom-externs.js
index afa094c02c..bc95b3ff8b 100644
--- a/polygerrit-ui/app/types/custom-externs.js
+++ b/polygerrit-ui/app/types/custom-externs.js
@@ -58,6 +58,5 @@ var FetchPromisesCache;
 var GrRestApiHelper;
 var GrDisplayNameUtils;
 var GrReviewerSuggestionsProvider;
-var moment;
 var page;
 var util;
\ No newline at end of file
diff --git a/polygerrit-ui/app/utils/date-util.js b/polygerrit-ui/app/utils/date-util.js
new file mode 100644
index 0000000000..44d9a17583
--- /dev/null
+++ b/polygerrit-ui/app/utils/date-util.js
@@ -0,0 +1,172 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const Duration = {
+  HOUR: 1000 * 60 * 60,
+  DAY: 1000 * 60 * 60 * 24,
+};
+
+export function parseDate(dateStr) {
+  // Timestamps are given in UTC and have the format
+  // "'yyyy-mm-dd hh:mm:ss.fffffffff'" where "'ffffffffff'" represents
+  // nanoseconds.
+  // Munge the date into an ISO 8061 format and parse that.
+  return new Date(dateStr.replace(' ', 'T') + 'Z');
+}
+
+export function isValidDate(date) {
+  return date instanceof Date && !isNaN(date);
+}
+
+// similar to fromNow from moment.js
+export function fromNow(date) {
+  const now = new Date();
+  const secondsAgo = Math.round((now - date) / 1000);
+  if (secondsAgo <= 44) return 'just now';
+  if (secondsAgo <= 89) return 'a minute ago';
+  const minutesAgo = Math.round(secondsAgo / 60);
+  if (minutesAgo <= 44) return `${minutesAgo} minutes ago`;
+  if (minutesAgo <= 89) return 'an hour ago';
+  const hoursAgo = Math.round(minutesAgo / 60);
+  if (hoursAgo <= 21) return `${hoursAgo} hours ago`;
+  if (hoursAgo <= 35) return 'a day ago';
+  const daysAgo = Math.round(hoursAgo / 24);
+  if (daysAgo <= 25) return `${daysAgo} days ago`;
+  if (daysAgo <= 45) return `a month ago`;
+  const monthsAgo = Math.round(daysAgo / 30);
+  if (daysAgo <= 319) return `${monthsAgo} months ago`;
+  if (daysAgo <= 547) return `a year ago`;
+  const yearsAgo = Math.round(daysAgo / 365);
+  return `${yearsAgo} years ago`;
+}
+
+/**
+ * Return true if date is within 24 hours and on the same day.
+ */
+export function isWithinDay(now, date) {
+  const diff = now - date;
+  return diff < Duration.DAY && date.getDay() == now.getDay();
+}
+
+/**
+ * Returns true if date is from one to six months.
+ */
+export function isWithinHalfYear(now, date) {
+  const diff = now - date;
+  return diff < 180 * Duration.DAY;
+}
+
+export function formatDate(date, format) {
+  const options = {};
+  if (format.includes('MM')) {
+    if (format.includes('MMM')) {
+      options.month = 'short';
+    } else {
+      options.month = '2-digit';
+    }
+  }
+  if (format.includes('YY')) {
+    if (format.includes('YYYY')) {
+      options.year = 'numeric';
+    } else {
+      options.year = '2-digit';
+    }
+  }
+
+  if (format.includes('DD')) {
+    options.day = '2-digit';
+  }
+
+  if (format.includes('HH')) {
+    options.hour = '2-digit';
+    options.hour12 = false;
+  }
+
+  if (format.includes('h')) {
+    options.hour = 'numeric';
+    options.hour12 = true;
+  }
+
+  if (format.includes('mm')) {
+    options.minute = '2-digit';
+  }
+
+  if (format.includes('ss')) {
+    options.second = '2-digit';
+  }
+  // en-GB is using h23 on Chrome 80, en-US is using h24 (midnight is 24:00)
+  const dtf = new Intl.DateTimeFormat('en-GB', options);
+  const parts = dtf.formatToParts(date).filter(o => o.type != 'literal')
+      .reduce((acc, o) => {
+        acc[o.type] = o.value;
+        return acc;
+      }, {});
+  if (format.includes('YY')) {
+    if (format.includes('YYYY')) {
+      format = format.replace('YYYY', parts.year);
+    } else {
+      format = format.replace('YY', parts.year);
+    }
+  }
+
+  if (format.includes('DD')) {
+    format = format.replace('DD', parts.day);
+  }
+
+  if (format.includes('HH')) {
+    format = format.replace('HH', parts.hour);
+  }
+
+  if (format.includes('h')) {
+    format = format.replace('h', parts.hour);
+  }
+
+  if (format.includes('mm')) {
+    format = format.replace('mm', parts.minute);
+  }
+
+  if (format.includes('ss')) {
+    format = format.replace('ss', parts.second);
+  }
+
+  if (format.includes('A')) {
+    if (parts.dayperiod) {
+      // Workaround for chrome 70 and below
+      format = format.replace('A', parts.dayperiod.toUpperCase());
+    } else {
+      format = format.replace('A', parts.dayPeriod.toUpperCase());
+    }
+  }
+  if (format.includes('MM')) {
+    if (format.includes('MMM')) {
+      format = format.replace('MMM', parts.month);
+    } else {
+      format = format.replace('MM', parts.month);
+    }
+  }
+  return format;
+}
+
+export function utcOffsetString() {
+  const now = new Date();
+  const tzo = -now.getTimezoneOffset();
+  const pad = num => {
+    const norm = Math.floor(Math.abs(num));
+    return (norm < 10 ? '0' : '') + norm;
+  };
+  return ` UTC${tzo >= 0 ? '+' : '-'}${pad(tzo / 60)}:${pad(tzo%60)}`;
+}
\ No newline at end of file
diff --git a/polygerrit-ui/app/utils/date-util_test.js b/polygerrit-ui/app/utils/date-util_test.js
new file mode 100644
index 0000000000..8fc785e588
--- /dev/null
+++ b/polygerrit-ui/app/utils/date-util_test.js
@@ -0,0 +1,114 @@
+/**
+ * @license
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import '../test/common-test-setup-karma.js';
+import {isValidDate, parseDate, fromNow, isWithinDay, isWithinHalfYear, formatDate} from './date-util.js';
+
+suite('date-util tests', () => {
+  suite('parseDate', () => {
+    test('parseDate server date', () => {
+      const parsed = parseDate('2015-09-15 20:34:00.000000000');
+      assert.equal('2015-09-15T20:34:00.000Z', parsed.toISOString());
+    });
+  });
+
+  suite('isValidDate', () => {
+    test('date is valid', () => {
+      assert.isTrue(isValidDate(new Date()));
+    });
+    test('broken date is invalid', () => {
+      assert.isFalse(isValidDate(new Date('xxx')));
+    });
+  });
+
+  suite('fromNow', () => {
+    test('test all variants', () => {
+      const fakeNow = new Date('May 08 2020 12:00:00');
+      sinon.useFakeTimers(fakeNow.getTime());
+      assert.equal('just now', fromNow(new Date('May 08 2020 11:59:30')));
+      assert.equal('a minute ago', fromNow(new Date('May 08 2020 11:59:00')));
+      assert.equal('5 minutes ago', fromNow(new Date('May 08 2020 11:55:00')));
+      assert.equal('an hour ago', fromNow(new Date('May 08 2020 11:00:00')));
+      assert.equal('3 hours ago', fromNow(new Date('May 08 2020 9:00:00')));
+      assert.equal('a day ago', fromNow(new Date('May 07 2020 12:00:00')));
+      assert.equal('3 days ago', fromNow(new Date('May 05 2020 12:00:00')));
+      assert.equal('a month ago', fromNow(new Date('Apr 05 2020 12:00:00')));
+      assert.equal('2 months ago', fromNow(new Date('Mar 05 2020 12:00:00')));
+      assert.equal('a year ago', fromNow(new Date('May 05 2019 12:00:00')));
+      assert.equal('10 years ago', fromNow(new Date('May 05 2010 12:00:00')));
+    });
+  });
+
+  suite('isWithinDay', () => {
+    test('basics works', () => {
+      assert.isTrue(isWithinDay(new Date('May 08 2020 12:00:00'),
+          new Date('May 08 2020 02:00:00')));
+      assert.isFalse(isWithinDay(new Date('May 08 2020 12:00:00'),
+          new Date('May 07 2020 12:00:00')));
+    });
+  });
+
+  suite('isWithinHalfYear', () => {
+    test('basics works', () => {
+      assert.isTrue(isWithinHalfYear(new Date('May 08 2020 12:00:00'),
+          new Date('Feb 08 2020 12:00:00')));
+      assert.isFalse(isWithinHalfYear(new Date('May 08 2020 12:00:00'),
+          new Date('Nov 07 2019 12:00:00')));
+    });
+  });
+
+  suite('formatDate', () => {
+    test('works for standard format', () => {
+      const stdFormat = 'MMM DD, YYYY';
+      assert.equal('May 08, 2020',
+          formatDate(new Date('May 08 2020 12:00:00'), stdFormat));
+      assert.equal('Feb 28, 2020',
+          formatDate(new Date('Feb 28 2020 12:00:00'), stdFormat));
+
+      const time24Format = 'HH:mm:ss';
+      assert.equal('Feb 28, 2020 12:01:12',
+          formatDate(new Date('Feb 28 2020 12:01:12'), stdFormat + ' '
+          + time24Format));
+    });
+    test('works for euro format', () => {
+      const euroFormat = 'DD.MM.YYYY';
+      assert.equal('01.12.2019',
+          formatDate(new Date('Dec 01 2019 12:00:00'), euroFormat));
+      assert.equal('20.01.2002',
+          formatDate(new Date('Jan 20 2002 12:00:00'), euroFormat));
+
+      const time24Format = 'HH:mm:ss';
+      assert.equal('28.02.2020 00:01:12',
+          formatDate(new Date('Feb 28 2020 00:01:12'), euroFormat + ' '
+          + time24Format));
+    });
+    test('works for iso format', () => {
+      const isoFormat = 'YYYY-MM-DD';
+      assert.equal('2015-01-01',
+          formatDate(new Date('Jan 01 2015 12:00:00'), isoFormat));
+      assert.equal('2013-07-03',
+          formatDate(new Date('Jul 03 2013 12:00:00'), isoFormat));
+
+      const timeFormat = 'h:mm:ss A';
+      assert.equal('2013-07-03 5:00:00 AM',
+          formatDate(new Date('Jul 03 2013 05:00:00'), isoFormat + ' '
+          + timeFormat));
+      assert.equal('2013-07-03 5:00:00 PM',
+          formatDate(new Date('Jul 03 2013 17:00:00'), isoFormat + ' '
+          + timeFormat));
+    });
+  });
+});
\ No newline at end of file
diff --git a/polygerrit-ui/app/yarn.lock b/polygerrit-ui/app/yarn.lock
index 5724ffa1ab..821b7247c0 100644
--- a/polygerrit-ui/app/yarn.lock
+++ b/polygerrit-ui/app/yarn.lock
@@ -338,11 +338,6 @@ isarray@0.0.1:
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-0.0.1.tgz#8a18acfca9a8f4177e09abfc6038939b05d1eedf"
   integrity sha1-ihis/Kmo9Bd+Cav8YDiTmwXR7t8=
 
-moment@^2.24.0:
-  version "2.24.0"
-  resolved "https://registry.yarnpkg.com/moment/-/moment-2.24.0.tgz#0d055d53f5052aa653c9f6eb68bb5d12bf5c2b5b"
-  integrity sha512-bV7f+6l2QigeBBZSM/6yTNq4P2fNpSWj/0e7jQcy87A8e7o2nAfP/34/2ky5Vw4B9S446EtIhodAzkFCcR4dQg==
-
 page@^1.11.5:
   version "1.11.5"
   resolved "https://registry.yarnpkg.com/page/-/page-1.11.5.tgz#0cfc8608be337f26f4377f31df0787aef0ca1af7"