0 */6 * * *
Cron reads this as: minute 0, past every 6th hour.
Next 5 runs
Computed in your browser's local time zone. Cron itself evaluates against the server's zone, which on most cloud hosts is UTC — see time zones & DST if that distinction matters here.
- Calculating…
When to use this schedule
Four runs a day — midnight, 06:00, noon and 18:00. Common for database maintenance, vacuum and compaction jobs, certificate renewal checks and anything where four attempts a day gives plenty of margin against a daily deadline.
What to watch out for
With only four runs a day, a job that silently fails can leave stale data for the best part of a day before anyone notices. This is firmly in dead-man's-switch territory: 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 while avoiding the midnight rush.
The crontab line
0 */6 * * * /usr/local/bin/your-job.sh >> /var/log/your-job.log 2>&1Redirect the output somewhere you will actually read it — by default cron mails it, and on a host with no mail transport that means it is discarded. 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
Need something this page does not cover? 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 collects sixty schedules in one place, and the guides cover crontab syntax, time zones, troubleshooting and production practices.