Cron Expression Calculator

How it works

fields: minute (0–59) hour (0–23) day-of-month (1–31) month (1–12) day-of-week (0–6, 0/7 = Sunday) · each supports * , a-b a-b/n */n and comma lists · when both day-of-month and day-of-week are set, either match fires the job

A cron expression is five space-separated fields that together define a repeating schedule. Each field is matched against the current minute, hour, day, month and weekday; the job runs on any minute where all five match. A field can be a wildcard (*), a single value, a range (9-17), a step (*/15 means every 15th value), a range-with-step (0-30/10), or a comma list (1,15,30). One classic quirk: when both the day-of-month and day-of-week fields are restricted, the job runs when either one matches — not both — so "0 0 13 * 5" fires on the 13th and on every Friday.

Worked example

The expression */15 9-17 * * 1-5 reads as "every 15 minutes, 9:00–17:00, Monday to Friday". The minute field */15 matches :00, :15, :30 and :45; the hour field 9-17 restricts it to business hours; and 1-5 in the day-of-week field limits it to weekdays — so it fires 36 times on each working day.

Sources: crontab(5) — POSIX cron format

Frequently asked questions