ToolWren › Cron

Cron Expression Explainer

Paste a 5-field cron expression to see what it means in plain English and exactly when it will next run. Perfect for sanity-checking schedules before you deploy them.

100% client-side · nothing is uploaded

Loading tool…

How to use the Cron

Type a 5-field cron expression (minute hour day-of-month month day-of-week).
Click Load sample to see an example if you're unsure of the syntax.
Read the plain-English meaning and the next 5 run times in your local time.
Adjust the expression until the schedule matches what you intend.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Cron

The five cron fields

A standard cron line has five fields: minute hour day-of-month month day-of-week. For example */15 9-17 * * 1-5 means every 15 minutes, 9am–5pm, Monday to Friday.

Reading the syntax

* means "every", */n means "every n", a-b is a range and a,b,c is a list. Day-of-week accepts 0–7 (0 and 7 are both Sunday) and month/day names like jan or mon.

Next-run preview

The tool simulates the schedule forward from now to show the next five fire times in your local time zone — the fastest way to confirm a cron does what you intend.

Frequently asked questions

How many fields should my cron have?

Five: minute, hour, day-of-month, month, day-of-week. (This tool doesn't include the optional seconds or year fields used by some systems.)

How are day-of-month and day-of-week combined?

Per POSIX cron: if both are restricted, the job runs when either matches. If only one is restricted, only that one applies.

Are the next-run times in my time zone?

Yes, they're shown in your browser's local time.