Run a Cron Job Twice an Hour
To run a job twice an hour, list two minutes in the minute field. For example 0,30 * * * * runs at :00 and :30 of every hour. Pick any two minutes with a comma.
The expression
0,30 * * * * fires at minute 0 and minute 30 of every hour — twice an hour, on the hour and half past. */30 * * * * does the same thing.
Choose other minutes
For :15 and :45 use 15,45 * * * *. Any two values 0–59 work.
Limit to certain hours
Twice an hour only during the day: 0,30 9-17 * * * runs on the hour and half-hour from 9 AM to 5 PM.
FAQ
What is the cron expression to run twice an hour?
0,30 * * * * runs at :00 and :30 of every hour. It's equivalent to */30 * * * *.
How do I run at :15 and :45 instead?
Use 15,45 * * * * — list the two minutes you want in the first field.
How do I limit a twice-an-hour job to work hours?
Add an hour range: 0,30 9-17 * * * runs twice an hour from 9 AM to 5 PM.