0 */6 * * *
Cron reads this as: minute 0, past every 6th hour.
Next 5 runs
These times are in your browser's local time zone. Cron itself uses the server's zone, which on most cloud hosts is UTC. If the difference matters here, see time zones & DST.
- Calculating…
When to use this schedule
It runs four times a day: midnight, 06:00, noon and 18:00. It is common for database maintenance, vacuum and compaction jobs, certificate renewal checks, and any job where four attempts a day leave plenty of margin before a daily deadline.
What to watch out for
With only four runs a day, a job that fails silently can leave data stale for most of a day before anyone notices. A schedule this sparse needs a dead-man's switch: have the job check in on success, and alert when a check-in does not arrive. Also consider whether midnight is the right anchor. 0 3,9,15,21 * * * keeps the same spacing and avoids the midnight rush.
The crontab line
0 */6 * * * /usr/local/bin/your-job.sh >> /var/log/your-job.log 2>&1Send the output to a log you will read. By default cron mails it, and on a host with no mail transport that mail is silently dropped. See the crontab guide for the surrounding syntax.
Related schedules
| Expression | Schedule |
|---|---|
0 3,9,15,21 * * * | Every 6 hours, offset by three |
0 */12 * * * | Twice a day |
0 */4 * * * | Every 4 hours |
Build your own
If this page doesn't cover the schedule you need, compose it field by field in the visual builder, or paste an expression you already have into the explainer for a per-field breakdown. The examples library has sixty schedules in one place, and the guides cover crontab syntax, time zones, troubleshooting and production practices.