What is the cron expression for every 30 minutes?

The expression is */30 * * * * or equivalently 0,30 * * * *. It runs at the top and bottom of every hour.

What is the difference between */30 and 0,30 in cron?

They produce the same schedule. */30 uses step syntax (every 30th minute from 0), while 0,30 explicitly lists the minutes. Both run at :00 and :30.

Cron Every 30 Minutes

*/30 * * * *

Every 30 minutes

Next 10 Executions

Times shown in UTC

Mon, May 18, 202608:30
Mon, May 18, 202609:00
Mon, May 18, 202609:30
Mon, May 18, 202610:00
Mon, May 18, 202610:30
Mon, May 18, 202611:00
Mon, May 18, 202611:30
Mon, May 18, 202612:00
Mon, May 18, 202612:30
Mon, May 18, 202613:00

Field Breakdown

*/30

Minute

Every 30 minutes

*

Hour

Every hour

*

Day of Month

Every day

*

Month

Every month

*

Day of Week

Every day of week

About This Schedule

The cron expression */30 * * * * runs a job every 30 minutes — at the top and bottom of every hour (:00 and :30). That's 48 executions per day.

Half-hourly schedules are very common for report generation, data aggregation, backup jobs, and email digest sending. The two-per-hour cadence is predictable and easy to communicate to stakeholders.

An equivalent expression is 0,30 * * * *, which explicitly lists minutes 0 and 30. Both produce the same schedule, but */30 is more concise and widely understood.