Cron Every 3 Hours
The 0 in the minute field pins the job to the top of the hour, and */3 in the hour field means "every 3rd hour." The job runs at 00:00, 03:00, 06:00, 09:00, 12:00, 15:00, 18:00, and 21:00 — eight times per day.
Cron Expression
0 */3 * * *Field Breakdown
| Field | Value | Meaning |
|---|---|---|
| Minute | 0 | At minute 0 (top of the hour) |
| Hour | */3 | Every 3rd hour (0, 3, 6, … 21) |
| Day of Month | * | Every day (1-31) |
| Month | * | Every month (1-12) |
| Day of Week | * | Every day of the week (0-6) |
Variations
0 */3 * * *Every 3 hours, on the hour30 */3 * * *Every 3 hours at half past (00:30, 03:30, …)0 */3 * * 1-5Every 3 hours on weekdays onlyCommon Use Cases
- Regular backups and snapshots
- Syncing data with third-party services
- Periodic cache warming or rebuilds
Tips & Best Practices
Always set the minute field (here 0) — leaving it as * would run every minute of those hours.
Since 3 divides evenly into 24, the schedule stays aligned every day.
Use the timezone-converter to confirm the run times in your users' timezone.