# Run a Cron Job Every 3 Hours

> The cron expression for every 3 hours is 0 */3 * * *: eight runs a day at 00:00, 03:00 … 21:00. Field meanings, next run times and offset variations.

```
0 */3 * * *
```

In plain English: At minute 0, every 3 hours.

0 */3 runs on the hour, every third hour: 00:00, 03:00, 06:00 and so on to 21:00 — eight runs a day. The leading 0 matters: without it (* */3 * * *), the job would fire every minute of those hours.

## Field by field

| Field | Value | Meaning |
|---|---|---|
| Minute | `0` | 0 |
| Hour | `*/3` | every 3 hours |
| Day of month | `*` | every day |
| Month | `*` | every month |
| Day of week | `*` | every weekday |

## Variations

- `30 */3 * * *` — at half past instead (00:30, 03:30 …)
- `0 1-23/3 * * *` — shifted to 01:00, 04:00 … 22:00
- `0 */3 * * 1-5` — every 3 hours on weekdays only

## FAQ

### Why does * */3 * * * run so often?

The asterisk in the minute field means every minute, so it fires 60 times in each matching hour. Set the minute explicitly: 0 */3 * * *.

### Does */3 reset at midnight?

Yes — hour steps restart each day. Because 3 divides 24 evenly, the interval stays a constant 3 hours across midnight anyway.

## Related schedules

- [0 */2 * * * — Run a Cron Job Every 2 Hours](https://www.devkult.com/cron/every-2-hours.md)
- [0 */4 * * * — Run a Cron Job Every 4 Hours](https://www.devkult.com/cron/every-4-hours.md)
- [0 */6 * * * — Run a Cron Job Every 6 Hours](https://www.devkult.com/cron/every-6-hours.md)

Open the interactive page: https://www.devkult.com/cron/every-3-hours