openstack-manuals/doc/contributor-guide/source/writing-style/num_and_units_of_measure.rst

Numbers and units of measure

When using numbers in running text, follow these guidelines:

• Spell out numbers from one to nine. However, use numerals for units of measure.
• Use Arabic numerals for numbers above ten.
• If a numeral starts a sentence, spell it out. For example: Five thousand environments have been deployed during the last six months.
• In one sentence, use either a spelled-out number or a numeral, not both.
• Use a comma if a numeral includes more than 4 digits. For example: 50,000.

In mathematical expressions:

• Use the x symbol for multiplication.
• Add a space between numbers and operators. For example: 256 x 2 = 512.

When using units of measure in running text, follow these guidelines:

• Use the corresponding unit symbol if a unit of measure comes immediately after a numeral.
  • Kb for kilobit
  • KB for kilobyte
  • kbps for kilobits per second
  • GB for gigabyte
  • Gbit for gigabit
  • MB for megabyte
• Do not pluralize an abbreviated unit of measure.
• Add a space between a numeral and a unit of measure.