Cron explainer · next runs · dialect translator
Decode any cron — and convert it anywhere.
Explain a cron expression in plain English, preview its next runs in any timezone, and translate it between Unix cron, GitHub Actions, AWS EventBridge, Quartz, systemd and Kubernetes — all in your browser.
At 09:00, on Monday.
Next 5 runs · UTC
- 2026-06-15 09:00 Monin 2d
- 2026-06-22 09:00 Monin 9d
- 2026-06-29 09:00 Monin 16d
- 2026-07-06 09:00 Monin 23d
- 2026-07-13 09:00 Monin 30d
Translations
- Unix / crontab
0 9 * * 1 - GitHub Actions
0 9 * * 1GitHub Actions runs cron in UTC only.
- Kubernetes CronJob
0 9 * * 1 - Quartz
0 0 9 ? * 2 - AWS EventBridge
0 9 ? * 2 * - systemd OnCalendar
Mon *-*-* 09:00:00
Try an example
*/15 * * * *Every 15 minutes0 9 * * 1-5Weekdays at 09:000 0 1 * *Midnight, 1st of the month30 3 * * 0Sundays at 03:30
Why cronwell
crontab.guru explains a single Unix expression. cronwell adds the parts you actually need when wiring jobs across platforms:
- Six dialects — Unix, GitHub Actions, k8s CronJob, Quartz, AWS EventBridge, systemd.
- Timezone-aware next runs — the next five fire times in any zone, with a relative estimate.
- The fiddly bits handled — seconds/year fields, Sunday=0 vs 1, and the Quartz/AWS "?" rule.
- Honest about limits — it flags conversions it can’t express exactly instead of guessing.
Frequently asked questions
Is cronwell free?
Yes — completely free, no account, no sign-up. It runs entirely in your browser.
What is a cron expression?
A cron expression is a compact schedule, usually five fields: minute, hour, day-of-month, month, and day-of-week. For example, "0 9 * * 1" means 09:00 every Monday. cronwell explains any expression in plain English and shows the next times it will fire.
Which schedulers can it translate between?
Unix/crontab, GitHub Actions, Kubernetes CronJob, Quartz, AWS EventBridge (cron), and systemd OnCalendar. Paste an expression in Unix, Quartz, or AWS form and cronwell shows the equivalent for all six.
Why do the dialects differ?
Quartz and AWS add a seconds and/or year field and number weekdays from 1 (Sunday) instead of 0, and require a "?" in either day-of-month or day-of-week. systemd uses a completely different OnCalendar format. cronwell handles the field shifts, the day-of-week renumbering, and the "?" rule for you.
Are the next-run times timezone-aware?
Yes. Pick any timezone (your local zone is detected automatically) and cronwell computes the next five runs in that zone, including a relative "in 2h 15m" estimate. Note that GitHub Actions always runs cron in UTC.
What does "day-of-month AND day-of-week" mean?
In standard cron, if both the day-of-month and day-of-week fields are restricted, the job runs when EITHER matches (an OR). Quartz and AWS cannot express that combination, so cronwell flags it when translating.
Does it support seconds, @yearly, or L/W/# specifiers?
cronwell focuses on the standard five-field cron plus Quartz/AWS field shifts. Quartz-only specifiers like L (last), W (weekday) and # (nth weekday) and shortcuts like @yearly are not yet parsed.