Cron Expression Parser

Parse and explain cron schedule expressions

minute (0-59) | hour (0-23) | day (1-31) | month (1-12) | weekday (0-6)

Common Examples

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About this tool

A cron expression parser turns the cryptic five-field syntax used by Unix cron, GitHub Actions, Kubernetes CronJobs, and most schedulers into plain English and shows the next several execution times. The fields are minute, hour, day-of-month, month, and day-of-week — each accepting wildcards (*), ranges (1-5), lists (1,3,5), and steps (*/15).

How to use

  1. Type a cron expression like 0 9 * * 1-5 into the input.
  2. Read the human-readable description that appears below — it confirms what your expression actually means.
  3. Inspect the next execution times to verify edge cases (month boundaries, leap years, etc.).
  4. Click any example expression to load it as a starting point.
  5. Copy the validated expression into your crontab, GitHub Actions workflow, or Kubernetes manifest.

Common use cases

  • Scheduling a daily database backup at 3 AM (0 3 * * *).
  • Running a CI workflow every Monday morning (0 9 * * 1).
  • Triggering a cleanup job every 15 minutes (*/15 * * * *).
  • Sending a weekly digest email Friday afternoon (0 17 * * 5).
  • Defining a Kubernetes CronJob to rotate logs at midnight on the first of each month.
  • Validating a tricky expression that uses ranges and steps before deploying it.

Frequently asked questions

Q. Why does my expression run at unexpected times?

A. Cron interprets day-of-month and day-of-week as OR (not AND) when both are restricted. * * 15 * 1 fires on the 15th OR every Monday — not just Mondays falling on the 15th.

Q. What time zone does cron use?

A. Whatever the host or container is configured for. GitHub Actions cron runs in UTC. Kubernetes CronJobs default to the cluster controller manager time zone unless you set spec.timeZone.

Q. Are 6-field cron expressions supported?

A. Some schedulers (Quartz, AWS EventBridge) add a seconds or year field. This parser uses the standard 5-field POSIX format.

Q. How do I run a job once at a specific time?

A. Cron itself does not have a one-shot mode. Use systemd timers, an at job, or an event-based trigger instead.