Cron library
Cron expression for every 12 hours
0 */12 * * *
At minute 0 past hour 0 and 12 every day.
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Or build one
Meaning
Next 10 run times
How to use
- Read the expression and the English meaning above. Confirm they match the job you have in mind.
- Use the time zone dropdown to preview the next 10 fire times in UTC or a US/EU city.
- Copy the expression into crontab, GitHub Actions (`on.schedule.cron`), or your job runner.
- If you need a nearby interval, browse the related schedules at the bottom of this page.
Twice a day is enough for a lot of housekeeping: certificate expiry scans, a second backup, or a merchandising feed. */12 matches hours 0 and 12.
Teams sometimes write 0 0,12 * * * instead. The two forms are equivalent and both read clearly in a pull request.
When this schedule is a good fit
Typical uses: A second daily backup besides the overnight one; Checking TLS expiry with a 12-hour alert window; Importing a catalog that updates morning and evening.
Cron fields are zone-naive. The daemon’s TZ — or the TZ= line above the job — decides what “midnight” or “9am” means. Preview both UTC and the office zone before you ship.
FAQ
Does this run at 12:00 midnight and 12:00 noon?
It runs at 00:00 and 12:00. Those are midnight and noon in the cron daemon’s time zone.
How do I run at 08:00 and 20:00?
0 8,20 * * *.
Does this page upload my crontab?
No. The explainer and the next-run list run in your browser. The expression on this page is a public example.