Cron Expression Parser
Parse cron expressions and preview the next run times.
Format: minute hour day month weekday. Examples: 0 9 * * 1-5 (weekdays at 9:00), */15 * * * * (every 15 min), 0 0 1 * * (1st of month).
About Cron Expression Parser
Cron expressions schedule tasks on Linux/Unix servers, in Kubernetes CronJobs, Jenkins, and countless CI/CD systems — yet the five-field syntax (minute, hour, day-of-month, month, day-of-week) is famously easy to get wrong. This parser validates any expression and shows the exact next five execution times, so you confirm the schedule before it runs in production.
Examples of common patterns: `*/5 * * * *` runs every 5 minutes; `0 9 * * 1-5` runs at 09:00 on weekdays; `0 0 1 * *` runs at midnight on the 1st of each month; `30 2 * * 0` runs at 02:30 every Sunday. The preview updates live as you edit — if the next runs do not match your intention, the expression is wrong, even if the parser accepts it.
A frequent pitfall: day-of-month and day-of-week interact — when both are restricted, most cron implementations run the job when either matches (OR logic), which surprises many people. This tool follows the standard Vixie cron semantics used by Kubernetes and most Linux distributions. The preview computes in your browser using local time; when configuring servers in UTC, adjust accordingly.
Frequently Asked Questions
What time zone does the preview use?
Your browser's local time. Servers usually run cron in UTC (or the container's configured zone), so shift the expected times accordingly — or temporarily set the schedule in the same zone you verify here.
Does it support @hourly or @reboot syntax?
The parser focuses on the standard five-field syntax. Descriptors like @hourly (0 * * * *) and @daily (0 0 * * *) can be entered in their expanded form.
Why do Kubernetes CronJobs behave differently?
Kubernetes uses the standard five-field format but in the controller's time zone (UTC by default) and does not run missed jobs. The expression syntax is identical, so validation here transfers directly.