Cron Expression Explainer
Paste a 5-field cron expression to see what it means in plain English and when it will next run.
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How to read a cron expression
- Paste a 5-field cron expression, or choose an example.
- Click Explain.
- Read what it means in plain English and the next 5 times it will run.
About this tool
This tool reads the standard 5-field cron format — minute hour day-of-month month day-of-week — supporting *, single values, ranges (1-5), steps (*/15, 1-31/2), comma-separated lists, and month/weekday names (JAN, MON). It also recognises the common nonstandard shortcuts @yearly, @monthly, @weekly, @daily, @hourly, and @reboot. The 6-field format with a leading seconds column (used by some non-standard schedulers, like Quartz) is not supported.
When both day-of-month and day-of-week are restricted (neither is *), standard cron treats them as an OR, not an AND — a run happens when either condition matches. The "next 5 run times" list is computed by walking forward minute-by-minute in your browser's own local time zone, so it's the authoritative answer if the plain-English description ever seems ambiguous. Nothing you enter is sent to a server — the entire tool runs as JavaScript in your browser tab.
Questions about cron
What do the five cron fields mean?
Minute, hour, day of the month, month and day of the week. 30 9 * * 1-5 means 09:30 every weekday.
How do I run something every 15 minutes?
Use */15 * * * *. To limit it to working hours on weekdays: */15 9-17 * * 1-5.
Why does my job run on more days than I expected?
When both day of the month and day of the week are set, cron runs when either matches, not both.
Does it support seconds?
No. It reads standard 5-field cron. Six-field formats with seconds, as used by Quartz, aren’t supported.