Cron Expression Generator

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What this tool does

Cron Expression Generator builds and explains cron schedules used by Unix/Linux cron, GitHub Actions, Kubernetes CronJobs, and similar schedulers. Edit the expression directly or fill in the individual minute/hour/day fields, and instantly see a plain-English description plus the next 5 times it would actually run.

How It Works

Each field is parsed into the exact set of values it matches: * expands to the field's full range, N-M expands to every value from N to M, N-M/S (or */S) keeps every Sth value in that range, and comma-separated items are combined together. A day is considered a match when its date satisfies the month field, and either the day-of-month field or the day-of-week field (both, if one of the two is left as "*"; either one, if both are restricted -- the standard cron OR rule).

To find the next run times, the tool starts from your current local time and jumps forward field by field -- straight to the next matching month if the current one does not qualify, straight to the next matching day if the month is fine but the day is not, and so on down to the minute (and second, if enabled). This field-by-field jump is what lets even a rare schedule like "29th of February only" resolve instantly to the next leap year instead of having to check every single day in between one at a time.

Problems it solves

• Writing a correct cron schedule for a server backup, CI/CD pipeline, or scheduled script without guessing field order.
• Reading an unfamiliar cron expression found in someone else's codebase or server configuration and understanding exactly when it fires.
• Double-checking that a schedule does what you think before deploying it, by looking at its actual next few run times.
• Working with the 6-field seconds variant used by Quartz, Spring Scheduler, and some Jenkins jobs, not just standard 5-field Unix cron.

Frequently asked questions