Free Tool
Cron Expression Builder
Turn a cron expression into plain English and preview exactly when it will next run. Start from a preset or write your own, it all runs in your browser. No signup needed.
This schedule means
At 09:00, Monday through Friday.
Next 5 runs
- Wed, Jul 29, 2026, 09:00 AM
- Thu, Jul 30, 2026, 09:00 AM
- Fri, Jul 31, 2026, 09:00 AM
- Mon, Aug 3, 2026, 09:00 AM
- Tue, Aug 4, 2026, 09:00 AM
Times shown in your local timezone.
A cron expression only says when a job should run, not whether it did. Sentinel's cron job monitoring alerts you when a scheduled run is late or missed.
See cron monitoringHow it works
Three steps, no signup.
Everything happens in your browser, nothing is sent to a server, and the explanation updates the instant you edit.
Enter or pick an expression
Start from a preset like every 15 minutes, or type your own five-field expression. Everything runs in your browser, so nothing is ever sent to a server.
Read it in plain English
We translate the minute, hour, day-of-month, month, and day-of-week fields into a single sentence, so you can confirm the schedule means what you intended.
Preview the next runs
We compute the next five run times from your expression and show them in your local timezone, updating instantly as you edit.
How is a cron expression structured?
A standard cron expression has five fields separated by spaces: minute (0 to 59), hour (0 to 23), day of month (1 to 31), month (1 to 12), and day of week (0 to 6, where 0 is Sunday). Each field accepts an exact value, a list such as 1,15, a range such as 1-5, a step such as */10, or a star meaning every value.
What does */5 mean?
The slash is a step. Applied to a star, */5 means every fifth value starting from the field's minimum. In the minute field, */5 runs at minute 0, 5, 10, 15 and so on, in other words every five minutes. You can also step within a range, so 0-30/10 in the minute field runs at minutes 0, 10, 20 and 30.
How is the day-of-week field numbered?
Day of week runs from 0 to 6, where 0 is Sunday, 1 is Monday, and 6 is Saturday. So 1-5 means Monday through Friday and 0,6 means the weekend. Note the special rule: when both day of month and day of week are set, cron runs when either matches, not only when both do.
Can Sentinel tell me when a scheduled job fails to run?
Yes. Sentinel's cron job monitoring watches for a heartbeat on the schedule you expect and alerts you when a run is late or missed entirely, so a silently failing backup or nightly job does not go unnoticed. See Sentinel's cron monitoring to set it up.
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