Cron Expression Explainer
Translate a cron expression into a sentence and next run times.
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About this tool
Reads a cron expression back in plain English and projects the next few fire times, so you can check a schedule before deploying it. Most cron mistakes are not typos — they are valid expressions that mean something other than what the author intended.
Limitations
- Standard five-field cron. Quartz six/seven-field expressions and vendor extensions such as @reboot are not the same syntax.
- Next run times are computed in your browser's local time zone.
Questions
- Why does my job run more often than I expected?
- If both day-of-month and day-of-week are restricted, POSIX cron fires when either matches, not both. “0 0 1 * 1” runs on the 1st and on every Monday.
- My scheduler rejects this expression.
- Schedulers disagree. Quartz adds a seconds field at the front, AWS EventBridge adds a year and requires a ? in one day field, and systemd timers use entirely different syntax.
- Which time zone are the projected runs in?
- This browser's local zone. Classic cron runs in the server's zone, which is frequently UTC — check before relying on the times shown.
Privacy
This page does its work in your browser. What you paste is processed by JavaScript running on your own device and is never sent to a DevToolery server — there is no server that could receive it. The page itself is a static file delivered by a CDN. See exactly what is stored.