Cron Expression Parser

Paste a cron expression to see what it actually means and exactly when it will next fire. Syntax errors are explained rather than just reported, and the next ten run times are calculated so you can confirm the schedule matches your intent.

Shorthands such as @daily and @hourly are understood, and month and day names (JAN, MON) work too.

How it works

A cron expression is five fields separated by spaces:

minute hour day-of-month month day-of-week

Each accepts a number, a list (1,15), a range (9-17), a step (*/5), or * for "every". Combined: */15 9-17 * * 1-5 means every fifteen minutes between 9am and 5pm, Monday to Friday.

The day-of-week trap. When day-of-month and day-of-week are both restricted, cron treats them as OR, not AND. So 0 0 1 * 1 runs on the 1st of the month and on every Monday — not only on Mondays that happen to fall on the 1st. This surprises nearly everyone, and the next-run list here makes it obvious.

Two more things that catch people out:

• Six fields is a different format. Quartz and Spring add a leading seconds field. Pasting a six-field expression into Unix crontab shifts every field by one, so a job you meant to run hourly runs at a completely different time.
• Timezone. Cron uses the server's local timezone, not yours. A job set for 02:00 runs at 02:00 wherever the server thinks it is — and during daylight-saving transitions a job can run twice or not at all.

On frequency: anything more often than once a minute is impossible, since minute is the smallest unit. If you need finer granularity, run a job every minute that loops internally, or use a proper queue worker.

Frequently asked questions