Dates and Times
Last edited on 23 Dec 2025
Use clear, unambiguous formats for all dates and times. Choose the format based on your audience and the technical context. Consistent formatting improves readability and prevents misinterpretation across regions and systems.
General Rules
Follow these general rules to keep dates and times consistent and easy for readers to understand.
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Always spell out the month in full. For example, “12 December 2025”.
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Do not use ordinal numbers for dates. For example, use “12 December,” not “12th December.”
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Use a space before “AM” and “PM.” For example, “5:00 PM”.
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Keep formatting consistent within the same document or example set.
Time Formats
Use the appropriate time format based on whether the content is user-facing or technical.
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Use a 12-hour clock with AM/PM for general user-facing content. For example, “5:00 PM”.
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Use 24-hour time (00:00–23:59) for technical contexts, such as logs, scripts, CLI output, API examples, and configuration files. For example, “17:00”.
Time Zones
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Include the time zone whenever a timestamp could apply to multiple regions or when coordinating across systems or users. For example, “5:00 PM ET,” “17:00 UTC”.
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Use UTC for universal timestamps, scheduled tasks, automated events, or any scenario that requires technical accuracy across distributed systems.
Clarity and Ambiguity
Use precise time expressions to prevent confusion and eliminate ambiguous interpretations.
- Avoid ambiguous phrases such as “midday,” “tonight,” or “end of day” when a specific time is required.