Random Time Generator

Random times of day

This random time generator picks an hour (0–23), a minute (0–59) and optionally a second (0–59), each uniformly at random, and formats the result as a clock time. Every minute of the day has the same chance of appearing, so over many runs the times are evenly spread from midnight to 23:59.

Random time generator formats

24-hour:               07:42   19:05   00:18
24-hour with seconds:  07:42:09   19:05:51
12-hour:               07:42 AM   07:05 PM   12:18 AM

In 12-hour format, midnight is shown as 12:xx AM and noon as 12:xx PM, following the usual convention. The 24-hour format always uses two digits for hours, which makes the values sort correctly as text.

Loading the times into a database or script

The 24-hour output with seconds, such as 14:37:09, is the format SQL TIME columns accept directly, so it is the safest choice for fixtures. 12-hour values need converting on the way in: MySQL reads them with STR_TO_DATE('2:37 PM', '%l:%i %p'), and PostgreSQL accepts '2:37 PM'::time.

For calculations, convert each time to seconds since midnight:

14:37:09 → 14 × 3600 + 37 × 60 + 9 = 52,629 s
00:00:00 → 0 s
23:59:59 → 86,399 s

Durations, averages and "is this within opening hours?" checks become simple integer comparisons. Remember that a span which crosses midnight, such as 22:00 to 02:00, needs 86,400 seconds added to the end time before you subtract.

What random times are useful for

• Test data – fill a TIME column, a booking form or an opening-hours widget with varied values.
• Edge cases – times around midnight and noon expose bugs in 12/24-hour conversion and in code that assumes a day starts at 1:00.
• Spot checks and reminders – schedule random check-in times so they cannot be anticipated.
• Games and exercises – practice reading clocks, converting between 12- and 24-hour time or calculating durations.
• Load testing – spread simulated events across a day rather than running them all at once.

Options

• How many – up to 10,000 times per run.
• Format – 24-hour or 12-hour with AM/PM.
• Seconds – add a random seconds component for timestamps that need it.
• Sort – put the times in order. In 24-hour format this is chronological order.

12-hour vs 24-hour time

The 24-hour clock is standard in most of the world and in computing (ISO 8601, databases, logs), while the 12-hour clock with AM and PM is common in the United States and a few other countries. Testing both formats catches the classic bugs: 12:30 AM converting to 12:30 instead of 00:30, or 12 PM being treated as midnight.

Limitations

The times are plain clock times with no date or time zone attached, so daylight-saving transitions are not considered. If you need full timestamps, the random date generator can produce date-time and ISO 8601 values in UTC. To add or subtract durations from a time, use the date and time calculator.

All values are generated with a secure random source in your browser and are not stored.