Cron Explainer

Understand a cron expression field by field

About this tool

Cron expressions define when scheduled tasks should run, but the five-field syntax is hard to read. This explainer breaks the expression down and shows what each field means: minute, hour, day of month, month and day of week.

It supports the most common operators: * (any value), */n (every n), ranges (a-b) and lists (a,b,c). Great for double-checking a schedule before putting it into production.

How to use

Type a 5-field cron expression (e.g. */5 * * * *).
See each field explained on its own line.
Adjust the expression until the description matches the schedule you want.

Frequently asked questions

How many fields does the expression have?

Five: minute, hour, day of month, month and day of week.

Does it support seconds (6 fields)?

No; we use the 5-field Unix/Linux cron standard.

What does */15 mean in the minutes field?

Every 15 minutes.