About Cron Expression Parser

Describe cron expressions in plain English with next run times. Part of the DevTools Surf developer suite. Browse more tools in the Generators collection.

Use Cases

• Verify CI/CD pipeline schedules before deploying
• Debug crontab entries that aren't firing when expected
• Convert human-readable schedules into cron syntax for GitHub Actions or Kubernetes CronJobs
• Preview next run times across daylight saving boundaries

Tips

• Click any preset to fill common patterns like daily, hourly, or weekly
• Edit individual fields (minute, hour, day, month, weekday) separately for precise control
• See the next 10 scheduled runs in your local timezone to verify the expression does what you expect

Fun Facts

• Cron was written by Ken Thompson for Unix in the 1970s. The name comes from Chronos, the Greek personification of time.
• The modern vixie-cron (written by Paul Vixie in 1987) is still the default cron daemon on most Linux distributions today.
• Cron has no built-in concept of timezone — jobs run in the system's local time, which has caused countless bugs during daylight saving transitions.

FAQ

Does it support all cron dialects?

Standard 5-field Unix cron, plus 6-field with seconds (Quartz, Spring), and special strings (@hourly, @daily). The dialect is auto-detected from the input.

What's the max future runs it shows?

Next 10 runs by default. Toggle up to 100 to spot seasonal patterns or check year-boundary behavior (February 29, daylight savings).

What about timezones?

The parser assumes UTC by default. Toggle to your local timezone to check when a job will actually fire from your perspective. DST shifts are handled.

Does it validate the expression?

Yes — out-of-range values (`60 * * * *`, `* * 32 * *`) get clear error messages. Much better than the 'it silently never fires' mode of real cron.