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Dates and times

Write dates and times using a consistent style that's clear to international audiences.

This page contains information on writing clock times. Write durations of time as measurements. For more information, refer to Units and measurements.


Dates include different elements, such as year, month, and weekday.

Use the following general formula to order the elements in a date:

Weekday, Month Day, Year

Depending on the context, you don't need to include all the elements in every date. Try to use an appropriate level of detail. For example, you often don't need to specify the weekday.

Write months and days of the week spelled out in words with initial capitals.

Use numerals for days and years. Always write years with four digits. Don't use ordinal numbers such as 1st, 12th, or 23rd in dates.

Use a comma between the day and the year. If you are only writing a month and a year, you don't need a comma.

The following table indicates valid date formats for different combinations of elements.

Weekday, Month Day, YearWednesday, October 21, 2015
Weekday, Month DayWednesday, October 21
Month Day, YearOctober 21, 2015
Month DayOctober 21
Month YearOctober 2015

Numeric dates

Avoid numeric dates as much as possible in your content.


Numeric dates are problematic for internationalization because conventions vary by region. The date 01/02/03 can mean different dates in the US, the UK, and China.

If you need to use a numeric date for space reasons, such as in a user interface, then use the format YYYY-MM-DD. Separate each element with a hyphen. Don't use a slash to separate elements.



Use numerals for all times. Use a colon to separate hours and minutes. Always specify the minutes, even if the value is zero.

Use the 12-hour clock and always specify "AM" or "PM." Capitalize "AM" and "PM" and leave a space between it and the time.

You can use "noon" instead of "12:00 PM" and "midnight" instead of "12:00 AM." Don't write "12 noon" or "12 midnight."

Don't use "24/7", "24-7," or related abbreviations. Instead, be specific about what you mean.

five o'clock5:00 PM
9.30am9:30 AM
3 in the afternoon3:00 PM
16:154:15 PM
available 24/7available every day

Time zones

Use time zones only when necessary to avoid confusion. For example, specify the time zone when discussing an event that readers outside of that time zone might want to attend.

Write the time zones after the time, using the full name of the time zone. Don't use abbreviations for time zone names.

Specify the difference from Coordinated Universal Time (UTC) in parentheses after the time zone name. If the difference isn't a whole number of hours, use a colon and write the number of minutes. Use the abbreviation "UTC" and don't use spaces between the plus or minus (−) signs. Don't use a hyphen in place of a minus sign.

For areas that use daylight savings, make sure that you use the correct time zone depending on the season. For example, time in Montreal changes from Eastern Standard Time during fall and winter to Eastern Daylight Time during spring and summer.

Don't use Greenwich Mean Time as a time zone. If you need to refer to time in the UK, use Coordinated Universal Time (UTC) for standard time and British Summer Time (UTC+1) for daylight savings time.

midnight Australian Central Standard Time (UTC+9.5)midnight Australian Central Standard Time (UTC+9:30)
8:00 AM Central Time (UTC-5)

(Note that this example uses a hyphen.)
8:00 AM Central Daylight Time (UTC5)
1:45 PM Greenwich Mean Time (UTC)1:45 PM Coordinated Universal Time (UTC)

Dates with times

If you need to write a date and time together, then write the date first followed by the word "at," then the time.

11:30 AM, Tuesday, September 19Tuesday, September 19 at 11:30 AM
May 25, 2022, 7:15 PMMay 25, 2022 at 7:15 PM

Ranges of dates and clock times

Write dates and clock times in ranges in full. Separate the start and end of the range with the word "to." Introduce the range with the word "from" as needed.

In ranges of time, always include the AM or PM indicator for both the start and end times. If you are specifying a time zone, write it once at the end of the time range.

Mon-FriMonday to Friday
October 15 2023October 1, 2023 to October 5, 2023
1:00 to 5:00 PM1:00 PM to 5:00 PM
10 AM2 PM Central European Standard Time (UTC+1)10:00 AM to 2:00 PM Central European Standard Time (UTC+1)

For ranges involving both dates and times, use the following formats:

Start and end times on the same datedate from start-time to end-timeMay 4, 2025 from 12:00 PM to 4:00 PM
Start and end times on different datesfrom start-date at start-time to end-date at end-timefrom Thursday, June 1 at 9:00 AM to Friday, June 30 at 5:00 PM