How can I write a Crontab that will run my script every 2 hours?

Use 0 */2 * * *: it runs at the top of every even hour (00:00, 02:00 … 22:00). For odd hours use 0 1-23/2 * * *. Cron matches clock times, not intervals.

How do you run a cron job every minute only on specific hours?

Use * 11,16,21 * * *: minute * with an hour list runs every minute during those three hours, 180 times a day. For one run per hour change the minute to 0.

How do I set up a cron job that runs every day at 1PM, 2PM and 3PM?

Use 0 13,14,15 * * *: an hour list runs at 13:00, 14:00 and 15:00 daily. 0 13-15 * * * is the equivalent range; different minutes need separate lines.

How can I run command every six hours every day? - Cron answer & example

Q: How can I run command every six hours every day?

Use 0 */6 * * *: four runs a day at 00:00, 06:00, 12:00 and 18:00, anchored at midnight. To shift the phase use a range, e.g. 0 3-23/6 * * * for 03/09/15/21.

Question

How can I run command every six hours every day?

Answer

Use 0 */6 * * * to run at the top of every sixth hour. With the standard hour range of 0 through 23, that means four runs each day: 00:00, 06:00, 12:00, and 18:00. This is a clock-aligned schedule, not an interval measured from deployment time or from the previous run's completion. If you need a different phase, select an explicit starting range; for example, 0 3-23/6 * * * runs at 03:00, 09:00, 15:00, and 21:00.

crontab

# at 00:00, 06:00, 12:00, and 18:00 every day
0 */6 * * *

Read 0 */6 * * * from left to right: minute 0 fixes each run at the top of the hour; */6 selects every sixth value in the hour field, starting from that field's minimum of 0; the day-of-month, month, and day-of-week wildcards allow every date. The scheduler's timezone determines what those clock times mean. If the host is unavailable at one of the matching times, standard cron moves on to the next scheduled match rather than running the missed occurrence when the host returns.

Run 0 */6 * * * on Crontap

Why this matters

The midnight anchor matters when you expect “six hours from now.” Starting or deploying the job at 10:00 does not shift this expression to 10:00, 16:00, 22:00, and 04:00; it still follows 00/06/12/18. Identical schedules across many hosts can also create a load spike at those four boundaries. Choose an explicit offset when needed, and use per-host staggering or concurrency controls when simultaneous runs would overload a shared database, API, or queue.

Read the dedicated guide: Cron every 6 hours.

Cron schedule used

What it does

0 */6 * * * — command

At 0 minutes past the hour, every 6 hours, every day.

Run in Crontap Cheatsheet

Calendar

View future cron matches in a calendar

September 2026 · UTC

0 runs

See this cron expression on the calendar view example

Cron every six hours each day

What it does

Calendar

Point Crontap at any URL. Pick any cron. Done.

What it does

Calendar

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