Cron every 30 minutes
Every 30 minutes in cron is */30 * * * * (Unix) or 0 */30 * * * ? (Quartz, Spring), at :00 and :30; next runs are calculated in your browser.
*/30 * * * *
0 */30 * * * ?
cron(0/30 * * * ? *)
Read by our parser as: Every 30 minutes. Open in the cron checker
Next 10 runs
Calculating in your browser...
- 1
- 2
- 3
At a glance
- Accepts
- Nothing to enter - the schedule is preset on the page
- Outputs
- The expression in Unix, Quartz/Spring and AWS form, plus its next 10 run times
- Where it runs
- Entirely in your browser, on your device
- What leaves your device
- Nothing - what you type stays in this tab
- Limits
- Run times use your browser's timezone or UTC; real schedulers can start a run late
- Account
- Not required - there is no sign-up
- Price
- Free, with no watermark and no usage cap
- Made by
- Visrut
What it means
*/30 * * * * runs twice an hour, at :00 and :30. It's identical to 0,30 * * * *. In Quartz and Spring it's 0 */30 * * * ?; Spring's own docs use the related 0 0/30 8-10 * * * to mean 8:00, 8:30, 9:00, 9:30, 10:00 and 10:30.
When this is the right schedule
Use it when the data you're pulling changes on a scale of hours, and half an hour is fresh enough: currency rates for display, a sitemap rebuild, a backup of a small database.
When to pick something else
Look elsewhere when you want "every 30 minutes from 9:15". Cron can do 15,45 * * * *, but not an arbitrary start time; for that use a rate-based schedule.
Things to watch
Shift it off the hour
15,45 * * * * is still every 30 minutes, just at quarter past and quarter to. On GitHub Actions, where the start of every hour is the documented busy time, that small shift can reduce delays.
Hour ranges are inclusive
*/30 9-17 * * * runs at 9:00, 9:30 and so on through 17:30, because 17 is included. To finish at 17:00 exactly, add a second line for 0 17 * * * and use 9-16 in the first.
AWS across midnight
AWS documents cron(0/30 20-2 ? * MON-FRI *): a range that wraps past midnight. Unix cron doesn't accept a backwards range; split it into 20-23 and 0-2.
Frequently asked questions
How do I run every 30 minutes between 9 AM and 5 PM?
*/30 9-16 * * * runs from 9:00 to 16:30; add 0 17 * * * if you also want 17:00. Using 9-17 gives you a 17:30 run too.
What is 0 0/30 * * * ? in Quartz?
Every 30 minutes at second 0: :00 and :30 of every hour. The leading 0 is seconds, and 0/30 in the minute field means start at 0 and step by 30.