Cron expression calculator: explain it and see when it runs

Plain English and real times

0 0 1 * MON becomes “At 00:00, on day 1 of the month, and also on Monday, since either day field matching is enough.” See the next and last runs and a countdown in any IANA time zone, not just your phone's.

Daylight saving, handled properly

On the spring-forward date a 02:30 job has no 02:30 to run at, and most schedulers lose the run silently. The app resolves every run against the full time zone database, marks skipped and repeated runs, and explains what Vixie cron, cronie, systemd timers and Kubernetes each do about it.

The mistakes, before you make them

• Both day fields set is an OR, not an AND
• Sunday is 0 in cron and 1 in Quartz
• 0 0 31 * * runs seven times a year, not twelve
• */25 leaves a ten-minute gap at the end of the hour
• A reversed range like 18-8 makes crontab reject the whole file

Four dialects, fourteen exports

Convert between Unix, six-field with seconds, Quartz and AWS EventBridge, with a reason when a schedule cannot be expressed. Export to crontab, Kubernetes, systemd, GitHub Actions, GitLab CI, Jenkins, Spring, Quartz, EventBridge, Celery, node-cron, Go cron, Laravel and APScheduler, each with its caveats. A visual builder and 45 presets are included.

Questions

What does */5 * * * * mean?

Every five minutes: at minutes 0, 5, 10 and so on, every hour of every day.

Does cron use my local time or UTC?

It depends on the scheduler. Classic cron uses the server's time zone, GitHub Actions uses UTC only, and Kubernetes needs version 1.27 or later for a time zone. The app shows runs in whichever zone you pick.

Why does my job run on the wrong days?

If both day-of-month and day-of-week are set, cron runs when either matches, not both. The app flags this and explains it.

Free on Google Play, supported by ads. Read the Cron Job Calculator privacy policy. Questions or a bug? Write to support@tahatec.com.