Cron Twice an Hour
Configure a cron job to run twice an hour at minutes 0 and 30 with 0,30 * * * *. Detailed field breakdown, practical examples, and scheduling tips.
Cron Expression
0,30 * * * *
Field Breakdown
| Field | Value | Meaning |
|---|---|---|
| Minute | 0,30 | At 0, 30 |
| Hour | * | Every hour (0–23) |
| Day of Month | * | Every day of the month (1–31) |
| Month | * | Every month (1–12) |
| Day of Week | * | Every day of the week (Sun–Sat) |
Detailed Explanation
The cron expression 0,30 * * * * schedules a task to run twice per hour, at the top of the hour and at the half-hour mark.
Field-by-field breakdown:
0,30(Minute): At minutes 0 and 30. The comma-separated list creates two execution points per hour.*(Hour): Every hour from 0 through 23. No restriction on which hour.*(Day of Month): Every day from 1 through 31. No restriction on the day of the month.*(Month): Every month from January through December. No restriction on the month.*(Day of Week): Every day of the week from Sunday through Saturday. No restriction on the day.
This means your task will execute 48 times per day, exactly at the top and bottom of every hour. This is functionally equivalent to */30 * * * * and provides the same twice-per-hour cadence. The explicit 0,30 notation is sometimes preferred for readability as it clearly shows the exact minutes of execution. This schedule is popular for data synchronization, cache refreshes, and feed polling. This expression is supported by standard cron on Linux/macOS, as well as cloud services like AWS CloudWatch, Google Cloud Scheduler, and GitHub Actions.
Use Case
Great for polling an RSS feed or webhook endpoint for new content and updating your application's content cache twice every hour.
Try It — Interactive Builder
Twice an hour, at :00 and :30
Next 10 Executions
Ctrl+Shift+C to copy expression