About this cron expression parser
A cron expression is the schedule format used by the Unix crontab, CI systems and many schedulers. It has five fields — minute hour day-of-month month day-of-week — where * means “every”, */10 means “every 10th”, 1-5 is a range, 1,15 is a list, and names like MON or JAN work in the last two fields (day of week accepts both 0 and 7 for Sunday). One subtlety this parser gets right: when you restrict both day-of-month and day-of-week, standard cron runs when either matches, not both — a common source of surprise schedules. The next-run preview is computed in your browser using your local timezone, so what you see is what your machine's crontab would actually do (servers often run in UTC — check your server's timezone when comparing).
Frequently asked questions
- What do the five fields mean?
- In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12 or JAN–DEC), and day of week (0–7 or SUN–SAT, where both 0 and 7 are Sunday).
- Why does my day-of-month plus weekday schedule fire more often than expected?
- Standard cron treats day-of-month and day-of-week as OR when both are restricted — “0 0 13 * FRI” runs on the 13th AND on every Friday, not only on Friday the 13th.
- Are the next run times in UTC?
- No — they're shown in your browser's local timezone. If your server runs in UTC, convert accordingly or set the server timezone.