Cron Expression: Every Hour on the Half Hour
The expression is 30 * * * * — it runs once an hour at minute 30 (e.g. 00:30, 01:30, 02:30). Paste it above to confirm the next runs.
The expression
30 * * * * runs a job at minute 30 of every hour — 00:30, 01:30, 02:30, and so on.
Field by field
30 fixes the minute. The hour, day-of-month, month, and day-of-week are all *, so it runs every hour of every day.
Shifting the offset
For the top of the hour use 0 * * * *. For quarter past use 15 * * * *. To run at both :00 and :30 (every 30 minutes) use */30 * * * * or 0,30 * * * *.
FAQ
What cron runs every hour on the half hour?
30 * * * * runs at minute 30 of every hour (00:30, 01:30, ...).
How is this different from */30?
30 * * * * runs once an hour at :30. */30 * * * * runs twice an hour, at :00 and :30.
How do I change the minute?
Replace 30 with any minute 0-59; for example 45 * * * * runs at quarter to each hour.