Cron Expression Explainer

Turn a cryptic five-field cron schedule into a sentence you can actually read.

Cron expression (minute hour day month weekday)

🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.

How it works

Cron is the scheduling syntax used by Unix systems, CI pipelines, and countless job runners. A standard expression has five fields — minute, hour, day-of-month, month, and day-of-week — and each can be a number, a list, a range, or a step like */15. It's powerful but famously hard to read at a glance.

This explainer parses each field and builds a plain-English sentence describing when the job fires, understanding wildcards (*), steps (*/n), ranges (1-5), lists (1,3,5), and named months and weekdays (mon, jan). Use the quick buttons to see common patterns, then tweak the fields to match your own schedule.

It runs entirely in your browser and is meant as a readability aid; always confirm the exact behaviour against your specific cron implementation, since a few systems extend the syntax.

Examples

0 9 * * 1-5 → At 09:00, on Monday through Friday.

*/15 * * * * → Every 15 minutes.

0 0 1 * * → At 00:00, on day-of-month 1.

Frequently asked questions

Which cron format does this use?

The classic five-field format: minute, hour, day-of-month, month, day-of-week. Six-field variants with seconds aren't parsed.

Does it support names like MON or JAN?

Yes — named weekdays and months are recognised and translated, as are ranges and lists of them.

Can it show the next run times?

It describes the schedule in words rather than computing exact future timestamps, which depend on the server's timezone.

Is anything sent to a server?

No. Parsing and explanation happen entirely in your browser.