Cron every 6 hours
0 */6 * * * — At 00:00, 06:00, 12:00 and 18:00 every day. 0 0,6,12,18 * * * is the same schedule written out.
Runs
Try one
The same schedule in every dialect
| Where | Expression | |
|---|---|---|
| Linux / Unix crontab, Kubernetes, GitHub Actions | 0 */6 * * * | explain |
| Quartz Scheduler | 0 0 0/6 ? * * | explain |
| AWS EventBridge | cron(0 0/6 * * ? *) rate(6 hours) | explain |
Spring @Scheduled | 0 0 */6 * * * | explain |
| Jenkins | H H/6 * * * | H calculator |
systemd timer OnCalendar= | *-*-* 00/6:00:00 | test |
AWS rate(6 hours) repeats at a fixed interval from when the rule or schedule was created, so it is not aligned to the clock the way the cron() form is.
Things to know
- A different phase is a range with a step:
0 3-23/6 * * *runs at 03:00, 09:00, 15:00 and 21:00. - The times are in the time zone the scheduler runs in — often UTC on hosted platforms. 00:00 UTC is 20:00 the previous evening in New York.
Variations
| Expression | Runs |
|---|---|
| 0 3-23/6 * * * | every six hours at 03:00, 09:00, 15:00, 21:00 |
| 0 0,6,12,18 * * * | the same schedule, as a list |
| 0 */6 * * 1-5 | every six hours on weekdays |
How to use this schedule
- Open your crontab with
crontab -e(or the scheduler's config file). - Add a line with the expression followed by the command:
0 */6 * * * /usr/local/bin/job.sh. Use absolute paths — cron runs with a minimalPATH. - Save. cron picks the change up automatically; check the next run times above, in the time zone your server uses.
- Redirect output if you want to keep it: append
>> /var/log/job.log 2>&1. The crontab line builder assembles the whole line.
FAQ
Is "0 */6 * * *" the same on every server?
The five-field form means the same thing in Linux cron, Kubernetes, GitHub Actions and most libraries. The clock it follows differs:
a Linux server uses its own time zone (or CRON_TZ on cronie), GitHub Actions and AWS EventBridge rules use UTC unless a time zone is configured, and Kubernetes uses the controller's zone unless .spec.timeZone is set.
Why do Quartz and AWS need a "?"
Both require exactly one of day-of-month and day-of-week to be ?, meaning "no specific value"; they refuse an expression that restricts both, or leaves both as *.
How do I check it will run when I expect?
The widget above lists the next runs in the time zone you choose, and flags any run that lands in a daylight-saving gap or a repeated hour. For a whole crontab, paste it into the crontab viewer.