Cron Parser

What the parser accepts

Fields take numbers, and the month and weekday fields also take three-letter English names in any case, alone or in ranges and lists: JAN-MAR, MON-FRI, SAT,SUN. Both 0 and 7 mean Sunday. A single value with a step, such as 5/15 in the minute field, runs from that value to the end of the range. The macros @hourly, @daily, @midnight, @weekly, @monthly, @yearly, and @annually are expanded; @reboot is not, because it has no times to list. Quartz-style ?, L, W, and #, and a seconds field, are not standard five-field cron and fail here.

Let the run list catch mistakes

The next runs reveal errors that read fine as text. * 9 * * * fires every minute from 09:00 to 09:59, not once; 0 9 * * * is once. A step restarts each hour, so */7 in the minute field runs at :56 and then :00, four minutes later. A range with a step, such as 0-30/10, runs at :00, :10, :20, and :30.

When both the day-of-month and weekday fields are restricted, a day matching either one runs: 0 0 13 * FRI fires on every 13th and on every Friday, not only on Friday the 13th. The search looks up to ten years ahead, so rare schedules such as @yearly or the leap-day 0 0 29 2 * still list their next dates. To have any schedule described in words, use the cron explainer.

How to use it

1. Enter a five-field expression or common macro.
2. Choose Parse schedule.
3. Compare UTC and local run times.

Privacy & limitations

Parsing is local. The result uses standard five-field cron semantics; a specific scheduler may use a different timezone or extensions.