Cron Explainer
Read a cron expression back field by field, and see when it will actually run.
Five fields: minute, hour, day of month, month, day of week. @daily and friends work too.
What each field means
When it runs next
Good to know
- Ranges, lists and steps are all understood: 1-5 is a range, 1,3,5 a list, */15 every fifteenth, and 9-17/2 both at once.
- Sunday is 0 and 7 alike, because both spellings are in use and a schedule should not depend on guessing which one a machine wants.
- When both the day of month and the day of week are restricted, cron runs if either matches — not both. That surprises people and is worth checking against your own schedule.
- Run times are worked out in your local zone by walking forward a minute at a time, up to a year ahead. A server usually runs on UTC, so check which clock yours uses.
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