Cron Expression Builder & Explainer
Build & explain cron expressions — free, instant, 100% in your browser.
format: minute hour day-of-month month day-of-week · supports * , - / and names (jan, mon…)
0 minute → minute 0 9 hour → hour 9 * day of month → every day of month * month → every month 1-5 day of week → day of week Monday through Friday
$ man cron
Cron's five-field syntax — minute, hour, day of month, month, day of week — is compact, powerful and famously easy to misread. A single misplaced asterisk is the difference between a job that runs once a day and one that runs every minute all day. This tool translates any expression into plain English instantly and shows the next scheduled run times, so you can confirm the schedule does what you think before it goes anywhere near a server.
It works in both directions. Paste an expression from an existing crontab, CI pipeline or Kubernetes CronJob to decode it, or start from a preset — every minute, hourly, nightly, weekdays at 9am, first of the month — and tweak the fields from there. Ranges (1-5), lists (1,15), and steps (*/10) are all supported.
The computed next-run times are the killer feature: seeing concrete timestamps removes all ambiguity about how day-of-month and day-of-week interact. Everything is calculated locally in your browser.