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CRON
readyType a 5-field cron expression - get a plain-English explanation and the next fire times. Or use the per-field inputs to build one.
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Field reference
| Field | Range | Special |
|---|---|---|
| Minute | 0-59 | * any · , list · - range · / step |
| Hour | 0-23 | same |
| Day-of-Month | 1-31 | same |
| Month | 1-12 | also JAN-DEC |
| Day-of-Week | 0-6 (Sun=0) | also SUN-SAT |
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Common cron patterns
The five-field expression below covers most real-world scheduling. Drop these into /etc/crontab, a Kubernetes CronJob spec, GitHub Actions schedule, or any standard cron runner.
| Expression | Meaning |
|---|---|
* * * * * | Every minute |
0 * * * * | Top of every hour |
*/5 * * * * | Every 5 minutes |
0 9 * * 1-5 | 9:00 AM, Monday through Friday |
30 2 * * * | 2:30 AM daily (a quiet window for nightly jobs) |
0 0 1 * * | Midnight on the 1st of every month |
0 0 * * 0 | Midnight every Sunday (weekly cleanup) |
15,45 * * * * | 15 and 45 minutes past every hour |
0 */6 * * * | Every 6 hours (00:00, 06:00, 12:00, 18:00) |
0 9 1-7 * 1 | 9 AM on the first Monday of each month |
Practical gotchas
- Day-of-month and day-of-week interact with OR, not AND.
0 0 1 * 1runs at midnight on the 1st OR every Monday, not on the 1st only when it's a Monday. To restrict to "first Monday," use0 0 1-7 * 1or your scheduler's day-of-week-with-position syntax. - Timezone is the runner's timezone, not UTC. A cron set at
0 9 * * *on a Linux server in Asia/Dubai runs at 9 AM Dubai time. Most cloud schedulers (AWS EventBridge, GitHub Actions) default to UTC; check the docs for what your runner uses. - Step values divide the range, not the unit.
*/15in the minute field means 0, 15, 30, 45 - it does NOT mean "every 15 minutes from now." Crontab evaluates wall-clock minutes against the pattern. - Sub-minute precision is not supported by standard cron. If you need every 30 seconds, run a script every minute that fires twice with
sleep 30, or use a different scheduler (systemd timers, k8s controllers). - Catch-up behaviour varies. If the runner is offline at fire time, some schedulers re-fire when it returns (anacron, k8s with concurrencyPolicy=Allow); others drop the missed run silently. Test your assumptions.
Common questions
Is Cron Expression Builder & Explainer free to use?
Yes. The tool runs in your browser at no cost, with no signup required.
Where is the math performed?
Calculations run locally in your browser. Your inputs do not leave your device.
Are the rates and rules current?
We update sources when published rates change. For high-stakes decisions, verify against the official source linked on this page.