Cheat Sheets · Cron Cheat Sheet · Cron Every 30 Minutes — Crontab Example

Cron Every 30 Minutes — Crontab Example

*/30 * * * *

Runs every 30 minutes — at minutes 0 and 30 of every hour.

Field by field

Field	Value	Meaning
`Minute`	`*/30`	Minutes 0 and 30
`Hour`	`*`	Every hour
`Day of month`	`*`	Every day
`Month`	`*`	Every month
`Day of week`	`*`	Every day of the week

Half-hourly is the classic metronome for sync jobs and status checks. To shift the pair to :05 and :35, use 5-59/30 * * * * — the range moves the step's starting point.

*/30 * * * * /usr/local/bin/pull-updates.sh

Related schedules

*/15 * * * * Every 15 minutes 0 * * * * Every hour, on the hour */10 * * * * Every 10 minutes

FAQ

Why does my 00:30 run vanish twice a year?
Daylight saving. When clocks spring forward, 02:30 local does not exist; fall back, it happens twice. Schedule in UTC to make it deterministic.

Is "twice an hour" exactly the same thing?
Functionally yes for cron. Some schedulers also accept 0,30 * * * * — identical result, written as a list.

Can I run it only during business hours?
Constrain the hour field: */30 9-17 * * 1-5 runs every half hour, 9:00–17:59, Monday to Friday.

Stop memorizing — build it interactively

Try this schedule in the Cron Editor

Full reference: Cron Cheat Sheet