Cron Expression Explainer
Paste a 5-field cron expression to read it in plain English and preview the next run times. Useful for sanity-checking a crontab line or a scheduled job before you ship it.
How to read a cron expression
- Paste your cron expression (minute, hour, day of month, month, day of week).
- Read the plain-English summary of when it runs.
- Check the list of upcoming run times to confirm the schedule is right.
Examples
Every weekday at 9am
0 9 * * 1-5
Runs at 09:00 on Monday, Tuesday, Wednesday, Thursday and Friday.
Every 15 minutes
*/15 * * * *
Runs every 15 minutes.
Frequently asked questions
What order are the cron fields in?
Five fields separated by spaces: minute (0-59), hour (0-23), day of month (1-31), month (1-12) and day of week (0-6, where 0 is Sunday). This tool uses the standard 5-field format, not the optional seconds or year fields.
What does */N mean?
A step value. For example */15 in the minute field means every 15 minutes (0, 15, 30, 45). You can also step a range, so 0-30/10 means 0, 10, 20 and 30.
How do day of month and day of week interact?
When both are set to something other than *, the job runs when EITHER one matches (a logical OR). If one of them is *, only the other field constrains the day. That OR behavior is the classic cron rule and trips up a lot of people.
What timezone are the run times in?
The previewed run times are computed in UTC so they are consistent everywhere. A real crontab usually runs in the server's local timezone, so adjust for any offset when you compare.
Is my cron expression sent to a server?
No. Parsing, the explanation and the run-time preview all happen in your browser. Nothing is uploaded.
Why do I see fewer than 5 run times?
Some expressions almost never fire, such as February 30th. The tool scans up to about a year ahead, so an impossible or extremely rare schedule can return fewer results.
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