Cron Explainer

About this tool

Cron expressions schedule tasks in Unix, CI/CD and job queues, but their compact syntax is hard to read at a glance. This explainer translates any expression — 5 fields (minute hour day month weekday) or 6 (with seconds), plus aliases like @daily or @reboot — into a natural-language description in your language, and lists the next 5 executions computed in your timezone. It uses cronstrue for descriptions and cron-parser for the calendar. Everything runs in the browser.

Use cases

• Verify what a cron expression will do before deploying it
• Check when a CI/CD job or crontab entry will run
• Learn cron syntax by reading natural-language descriptions
• Debug schedules that don't fire when expected

Frequently asked questions

Which expression formats are accepted?

Standard 5-field expressions (minute hour day-of-month month day-of-week) and 6-field ones with seconds first. Predefined aliases like @yearly, @monthly, @weekly, @daily, @hourly and @reboot are also accepted.

In which timezone are the next executions computed?

In your browser's timezone, which is how local crontabs usually behave. Dates are shown using your language's regional format.

Why doesn't @reboot show upcoming executions?

@reboot means 'run at system startup', with no time-based schedule. That's why the description appears but the next-runs list stays empty.

Are month and day names (MON, JAN) supported?

Yes, abbreviated English names for months and weekdays are valid in their respective fields.