Cron Expression Generator & Explainer

About this tool

This tool builds and explains cron schedules. Type an expression and it translates the schedule into plain English and lists the next five run times in your local timezone. The presets cover the common cases, and the field accepts anything you paste from an existing crontab.

Cron syntax is compact and easy to misread, and the cost of getting it wrong is a job that runs sixty times an hour or never runs at all. The five fields, in order, are minute, hour, day-of-month, month and day-of-week. Seeing the actual next run times is the quickest way to confirm an expression means what you think it means. Everything is calculated in your browser and no data is sent anywhere. Scheduling and job orchestration are part of our infrastructure automation & DevOps work.

How to use it

Start from a preset or paste your own expression.

• Enter five space-separated fields: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12) and day-of-week (0-7, where 0 and 7 both mean Sunday).
• Use * for every value, */n for steps, a-b for ranges and commas for lists.
• Read the plain-English summary to confirm the intent.
• Check the next five run times. If they are not what you expected, the expression is wrong rather than the preview.

Common questions

What order are the cron fields in?

Minute, hour, day-of-month, month, day-of-week. A frequent error is transposing the first two fields: 2 0 * * * runs at 00:02, while 0 2 * * * runs at 02:00.

What happens if I set both day-of-month and day-of-week?

Standard cron treats them as OR, not AND. When both fields are restricted, the job runs on days matching either one. So 0 0 13 * 5 runs on the 13th of every month and on every Friday, not only on Friday the 13th.

Which timezone does cron use?

The system or daemon timezone, commonly UTC on servers, while this page previews runs in your browser's local time. Jobs scheduled during a daylight saving transition can be skipped or repeated, so keep sensitive work outside that window or run the host in UTC.