Cron Expression Builder & Tester
Pick a common schedule preset or write a standard 5-field cron expression, then see the next five times it would actually run. Supports the widely-used Vixie cron / crontab dialect with wildcards, ranges, lists, and step values.
All calculations happen on your device — the cron expression is never sent to any server.
This tool supports the standard 5-field cron format (minute, hour, day-of-month, month, day-of-week) used on Unix/Linux systems (crontab).
minute hour day-of-month month day-of-week
What this tool does
Parses a cron expression and shows its upcoming run times as readable dates, with presets for the common patterns.
When to use it
- Writing a scheduled job and wanting to confirm it runs when you intend.
- A cron expression exists in your system and you cannot tell when it fires.
- Debugging a job that runs at the wrong time.
- Learning cron syntax by trying expressions and seeing the effect.
How to use it
- Pick a preset, or type the expression into the expression field.
- Run the calculation.
- Read the upcoming run times to confirm they are what you expect.
A practical example
Input
The expression 0 9 * * 1
Output
A list of upcoming runs, all at nine in the morning every Monday.
Limitations
- The supported syntax is standard five-field cron (minute, hour, day of month, month, day of week) in the usual Vixie cron dialect used by crontab.
- Supported: wildcards, comma lists, ranges and step values. System-specific extensions — a seconds field, a year field, special names — are not supported.
- Times are computed in your device's time zone, and your server may run in a different one — a common reason a job fires at an unexpected hour.
- An invalid expression is rejected with a clear message.
Privacy and processing
All calculations happen on your device and the cron expression is never sent to any server.
Technical notes
- Upcoming runs are found by scanning minute by minute from now — simple, correct, and fast enough for a preview of a handful of runs.