Midnight vs. Noon Formatting
Noon and midnight are clearer than 12 AM/12 PM because readers can interpret the numeric labels inconsistently. Microsoft and Australian Government style guidance recommend using the words, and Microsoft notes that midnight begins the new day.
For clarity, write “noon” (or “midday”) and “midnight” instead of relying on 12 AM and 12 PM. When midnight is tied to a date or deadline, make the day boundary explicit.
Key details
Important caveats
Date Boundary
When a deadline is at midnight, include enough date context to make the intended boundary clear.
Further guidance
Clarity Rule
Prefer the words “noon”/“midday” and “midnight” when clarity matters instead of relying on 12 AM or 12 PM.
Practical Application
Prefer the words “noon” (or “midday”) and “midnight” when 12 a.m./p.m. could be misread. For deadlines or schedules at midnight, state the date boundary explicitly so readers know which day is ending or beginning.
Reader Check
Could a reader interpret the stated time without having to remember how your system assigns 12 a.m. and 12 p.m., especially at a date boundary?
Worked Example
Write “The office closes at noon” and, for a deadline, “Submit by midnight at the end of 30 September” rather than relying on an ambiguous “12:00 a.m.” alone.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Date and time terms — Microsoft Style Guide (opens in a new tab)Microsoft · Official Microsoft house-style guidance for dates and times, including date ordering and formatting examples.
- Dates and time — Australian Government Style Manual (opens in a new tab)Australian Government Style Manual · Australian Government guidance for day–month–year dates, ordinal dates, decades, centuries, time zones, and en-dash spacing in date/time spans