Cron Expression Tester
Check a cron expression, read it back in plain English, and see the next times it will actually fire.
30
minute
0–59
9
hour
0–23
*
day of month
1–31
*
month
1–12 or JAN–DEC
1-5
day of week
0–6 or SUN–SAT
Valid
At 09:30, on Monday, Tuesday, Wednesday, Thursday and Friday.
Next runs
Calculating…
Runs entirely in your browser — nothing you paste is uploaded or stored.
About cron expression tester
Cron syntax is five terse fields, and the failure mode is silent: a valid expression that fires far more or far less often than you intended. Nothing tells you until the job has been running for a week.
So the useful check is not "is it valid" but "when does it actually run". This lists the next occurrences, computed from the expression, which makes an accidental every-minute schedule obvious immediately.
Good to know
- Five fields: minute, hour, day of month, month, day of week. Supports * , - / and named months and days.
- The classic mistake is setting day-of-month and day-of-week together. In standard cron they are OR-ed, not AND-ed, so the job runs on either — which is rarely what people expect.
- Times are computed in your local timezone. A server running in UTC will fire at different wall-clock times, which is worth checking before relying on an overnight schedule.