0 */4 * * *
Cron reads this as: minute 0, past every 4th 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 six times a day, at 00:00, 04:00, 08:00, 12:00, 16:00 and 20:00. This interval suits jobs that are expensive enough to matter but not urgent, such as full index rebuilds, third-party data pulls with per-call costs and moderate report generation.
What to watch out for
No run lands inside the 02:00 daylight saving hour, but the interval around it changes length. If the host runs in a zone that observes DST, the 00:00 to 04:00 gap becomes three hours in spring and five in autumn. Scheduling in UTC avoids the issue entirely. At this frequency, alert on missed runs as well as on failures.
The crontab line
0 */4 * * * /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 */6 * * * | Every 6 hours |
0 */3 * * * | Every 3 hours |
0 1,5,9,13,17,21 * * * | Every 4 hours, offset by one |
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.