0 */4 * * *
Cron reads this as: minute 0, past every 4th 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
Six runs a day at 00:00, 04:00, 08:00, 12:00, 16:00 and 20:00. A comfortable cadence for jobs that are expensive enough to matter but not urgent — full index rebuilds, third-party data pulls with per-call costs, moderate report generation.
What to watch out for
Four hours is long enough that a run landing during a daylight saving transition is a real possibility over a year. If the host runs in a zone that observes DST, the 00:00–04:00 leg is the one that shifts; scheduling in UTC removes the question entirely. At this frequency you should also be alerting on missed runs, not just failures.
The crontab line
0 */4 * * * /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 */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
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.