How to use the Cron Expression Explainer
- Type a cron expression or click an example chip.
- Read the explanation.
- Check the next run times before deploying.
About this tool
Cron is the Unix scheduler behind backups, reports, cache warmers and countless CI jobs. Its five fields — minute, hour, day of month, month, day of week — are compact but easy to misread. One wrong asterisk can turn a nightly job into one that fires every minute.
| Syntax | Meaning | Example |
|---|---|---|
* | every value | * * * * * every minute |
*/n | every n | */15 * * * * every 15 min |
a-b | range | 0 9-17 * * * hourly 9–17 |
a,b | list | 0 0 1,15 * * 1st & 15th |
One classic gotcha: if both day-of-month and day-of-week are restricted, cron runs when either matches. Our next-run preview follows that rule. Learn more in our cron jobs guide.
Frequently asked questions
Does it support seconds?
Standard cron has 5 fields. Quartz and some cloud schedulers add seconds or years — strip those first.
Is 0 or 7 Sunday?
Both mean Sunday.
Which time zone does cron use?
The server's local zone unless configured (e.g. CRON_TZ). Our preview uses your browser's zone.