How to use
- Type a cron expression, or press one of the examples such as Weekdays at 09:00.
- Read the description in words and the list of upcoming runs. Choose how many runs to show.
- Pick UTC or your own time zone, because the same expression runs at different moments depending on the zone.
Examples
*/15 * * * *
→ Every 15 minutes
0 9 * * 1-5
→ At 09:00, Monday through FridayFields are minute, hour, day of month, month and day of week.
0 0 1 * 1
→ Runs at midnight on the 1st of every month and also on every MondayWhen both day of month and day of week are set, a run happens if either one matches.
How it works
The description is written by the open-source cronstrue library. The upcoming run times are calculated by the open-source cron-parser library: starting from the current moment, it finds the next time that matches every field, in the time zone you choose.
Times are shown for the selected zone, including daylight saving changes for zones that have them. The list is calculated on your device and updates whenever you change the expression, the number of runs or the zone.
The tool explains an expression and lists its runs; it does not run anything and does not connect to any scheduler.
Sources
- crontab(5) manual page: the crontab file format
- cronstrue (descriptions) and cron-parser (run times), the open-source libraries used here
Frequently asked questions
- What are the five fields of a cron expression?
- In order: minute (0-59), hour (0-23), day of month (1-31), month (1-12 or JAN-DEC) and day of week (0-6 or SUN-SAT, where 0 and 7 both mean Sunday). A star means every value, a slash gives a step such as */15, a comma lists values and a dash gives a range.
- Can I use seconds?
- Yes. With six fields the first one is seconds, for example 30 */10 * * * *. Standard cron has no seconds field, so check that your scheduler supports it before using one.
- What happens when I set both day of month and day of week?
- The job runs when either field matches, not when both match. So 0 0 1 * 1 runs on the 1st of every month and on every Monday. This is how classic Unix cron behaves, but some schedulers differ.
- Are shortcuts like @daily supported?
- Yes, the common ones such as @hourly, @daily, @weekly, @monthly and @yearly work in the run list. The wording below the expression may not cover every shortcut.
- Does this match my scheduler exactly?
- Not always. Cron-like schedulers differ in details such as seconds, a year field, and special characters. GitHub Actions, Kubernetes and cloud schedulers each have their own rules and usually run in UTC, so check their documentation for anything critical.