Cron Expression Parser

What the cron expression parser tells you

A generator answers "what should I write?". The parser answers "what will this actually do?". That matters when you inherit a crontab, a CI schedule, a Helm chart or an event rule. It labels every field, lists the values each field resolves to, shows the next runs in the time zone you pick and draws a week-by-hour heatmap so a surprising schedule stands out.

Cron calculator: find the next run times

A cron calculator answers one practical question: given this expression, when does it run next? Paste the expression, choose a time zone, and the parser lists the upcoming runs in that zone, so you can check a schedule without waiting for it to fire. The calculation follows the same rules as the other tools, including daylight saving transitions.

Reading an expression

Read left to right. The minute field decides when inside the hour the job can run, the hour field which hours are eligible, and day-of-month, month and day-of-week narrow the calendar. Small changes matter: */5 * * * * runs every five minutes, while 5 * * * * runs once an hour at minute 5.

The symbols ?, L, W and # exist only on some platforms (AWS EventBridge and Quartz). Choose the platform in the validator to see them handled correctly.