EpochLab

Cron Expression Parser

What does this cron expression do?

Paste an expression and get it back in English, field by field, with its next runs, how often it fires, and any trap it has walked into.

Questions people ask

The things that come up about cron expression parsers, answered plainly.

What does '0 0 1 * 1' actually run on?

The 1st of every month *and* every Monday — not Mondays that fall on the 1st. When both day-of-month and day-of-week are restricted, cron ORs them. It is the single most surprising rule in cron, and the page flags it whenever it applies.

Which time zone does a cron job use?

The system's local time, unless the runner says otherwise — which means a job scheduled for 02:30 does not run on the morning the clocks go forward. The next-run list is computed in the zone you select and skips non-existent times the same way.

Related tools

Julian days, Excel serials, GPS time, cron expressions and format validators.

Cron Human Readable ConverterOne sentence describing what an expression does, plus a field-by-field breakdown — for putting in a comment, a runbook or a pull request description.
Cron Expression GeneratorPick a schedule and get the expression, described back to you in English and with its next five runs shown — so you can see what it does before it does it.
Cron Expression ValidatorChecks the syntax, names the field that failed, and warns about the expressions that are valid but never fire — 30 February being the classic.
Recurring Date GeneratorDaily, weekly, monthly or yearly, with intervals and by-weekday rules — the dates listed with their weekdays, and the RFC 5545 RRULE beside them.

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