Developer / SEORuns in your browser

Cron Expression Explainer

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

Quick presets

Cron expression

Try:

In plain English

–

Fields

Next runs

Syntax cheat-sheet

Runs in your browser — nothing you enter is uploaded or stored.

ToolFeather · Plain English

Scratchpad auto-saved

Stored in this browser (localStorage)

About the Cron Expression Explainer

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

4 answers

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.