Cron explainer

When does it run?

Linux crontab syntax: minute, hour, day of month, month, day of week. Calculated in your browser.

Every 5 minutes Every hour Daily at 02:30 Weekdays at 07:00 Every 15 min, business hours Sundays at 03:00 1st of the month, 06:00 Quarterly Twice a day

Every 5 minutes

*/5Minute

*Hour

*Day of month

*Month

*Day of week

Next runs (Europe/Vienna)

Fri 2026-10-16 19:10
Fri 2026-10-16 19:15
Fri 2026-10-16 19:20
Fri 2026-10-16 19:25
Fri 2026-10-16 19:30
Fri 2026-10-16 19:35
Fri 2026-10-16 19:40
Fri 2026-10-16 19:45
Fri 2026-10-16 19:50
Fri 2026-10-16 19:55

Times skipped by a daylight-saving change are not listed (cronie runs them right after the switch).

Details

Minute	`*/5`	every 5
Hour	`*`	every
Day of month	`*`	every
Month	`*`	every
Day of week	`*`	every

systemd timer

OnCalendar=*-*-* *:00/5:00

Syntax

┌───────────── minute        0–59
│ ┌─────────── hour          0–23
│ │ ┌───────── day of month  1–31
│ │ │ ┌─────── month         1–12 or JAN–DEC
│ │ │ │ ┌───── day of week   0–7 or SUN–SAT (0 and 7 = Sunday)
│ │ │ │ │
* * * * *  command

*: every value
1,15: list
1-5: range
*/15: every 15th value (0, 15, 30, 45)
8-17/2: every 2nd value within a range
@daily: @hourly, @daily, @weekly, @monthly, @yearly, @reboot

If both day of month and day of week are restricted, cron runs when either matches. Cron uses the server's time zone (or CRON_TZ= in the crontab).

Same in the terminal

$ curl tools.otw.solutions/cron/*/5_*_*_*_*

Or with spaces: curl "tools.otw.solutions/cron?e=0+3+*+*+1-5" · JSON: add ?format=json