Numbers

Use number formatting that supports clarity, consistency, and technical accuracy. Apply numeral and word usage intentionally, with attention to technical context, readability, and product conventions.

General Principles

When writing numbers:

• Spell out numbers less than 10 and numbers that begin a sentence.
• Use numerals for 10 and above, unless the number begins a sentence.
• When a sentence contains multiple numbers and any are 10 or greater, use numerals for all numbers in that sentence to maintain consistency. For example, “The cluster uses 3 controllers and 14 workers.”

Units, Currency, and Ranges

Use numerals when numbers are paired with units, currency, or ranges.

Use numerals with bits and bytes, currency, and measurements.

Use a space between numbers and units.

Do not pluralize abbreviated units.

Decimals and Percentages

Use numerals for decimals and percentages.

Include a leading zero for values less than one.

Limit fractional precision to no more than four decimal places, unless a product explicitly outputs more.

Ordinals

Use numerals for ordinals in technical contexts such as versioning, steps, iterations, or sequences. For example, “Upgrade to Version 2 of the API.”

Use numerals for ordinals 10 and above. For example, “the 25th deployment,” and “the second attempt.”

Use numerals for ordinal ranges.

Spell out ordinals below 10 when they are not technical or do not represent dates.

Do not add -ly to ordinal numbers.

Use First, Second, Third instead of Firstly, Secondly, or Thirdly.

Versions, Identifiers, and Names

Preserve numbers exactly as they appear in product names, identifiers, protocols, and standards.

For version references that include patch-level ranges, use x for unspecified components.

Ranges

Use a hyphen (-) for numeric ranges.