Preset
Cron expression for every 30 minutes
*/30 * * * *Cron expression5-field
Every 30 minutes
Lint
OKNo issues found — this expression is well-formed.
Next runs
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What it does
The expression */30 * * * * runs a job twice an hour, on the hour and on the half hour — at :00 and :30 — every hour of every day. Because 30 divides 60 exactly, the two runs are evenly spaced and the pattern resets cleanly each hour.
Half-hourly is a comfortable cadence for moderately important background work: refreshing reports, reconciling records, or checking a slow-changing external source. It keeps data reasonably fresh while staying light on resources and logs.
It is equivalent to the explicit 0,30 * * * *. To bound it to a window, add hour and weekday fields — */30 9-17 * * 1-5 runs on the hour and half hour from 9 AM to 5:30 PM on weekdays. Note that 9-17 includes the 5 PM hour, so the last run is 17:30.
Related presets
* * * * *
every minute
*/5 * * * *
every 5 minutes
*/15 * * * *
every 15 minutes
*/10 * * * *
every 10 minutes
*/20 * * * *
every 20 minutes
0 * * * *
every hour
FAQ
What times does */30 run?
On the hour and the half hour — :00 and :30 — 48 runs a day.
Is */30 the same as 0,30 * * * *?
Yes, they are identical. Use whichever reads more clearly in your crontab.
How do I run every 30 minutes only on weekdays?
Set the day-of-week field:
*/30 * * * 1-5 runs every half hour, Monday through Friday.