Cron expression explainer

Cron syntax in one table

Special characters: * means every value, , separates a list, - defines a range and / sets a step. Shortcuts such as @daily, @hourly and @weekly are also accepted.

Common schedules

• */5 * * * *: every five minutes.
• 0 * * * *: at the top of every hour.
• 0 0 * * *: every day at midnight.
• 30 8 * * 1-5: weekdays at 8:30.
• 0 0 1 * *: on the first day of every month.
• 0 3 * * 0: every Sunday at 3:00.

The day-of-month and day-of-week trap

If you set both day fields, standard cron runs the job when either matches, not both. 0 9 1 * 1 runs on the first of the month and on every Monday. The explainer calls this out. To run only on a Monday that falls on the first, schedule it on Mondays and check the date inside the job.

Time zones

Cron runs in the scheduler's time zone. A Linux crontab uses the server's zone; Kubernetes CronJobs default to the controller's zone unless you set spec.timeZone; GitHub Actions schedules always run in UTC. The next-run times on this page are shown in your browser's local time.

FAQ

Does this support 6-field cron with seconds?

No. It explains standard 5-field cron, used by crontab, Kubernetes and GitHub Actions. Quartz and Spring use a 6- or 7-field format with seconds.

Why does GitHub Actions run my schedule late?

Scheduled workflows can be delayed during periods of high load, especially at the top of the hour. Pick an odd minute such as 17 to reduce delays.

What does */15 mean?

Every 15th value in the field's range. In the minute field it means minutes 0, 15, 30 and 45.

Is it free?

Yes. All tools at ryzlabs.com/tools are free with no sign-up.