What is Cron expression?
Also known as: crontab schedule, cron syntax.
Last updated: July 2026
- Cron expression
- A cron expression is a string of five (sometimes six) fields that tells the Unix cron scheduler when to run a task: minute, hour, day-of-month, month and day-of-week. For example, 0 9 * * 1 means 09:00 every Monday. An asterisk (*) means 'every' value for that field.
Explain a cron expression in plain English and see its next run times. Free, instant, in-browser cron parser.
The five fields
In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12) and day of week (0–7, where 0 and 7 are both Sunday). Fields accept lists (1,15), ranges (1-5) and steps (*/15 = every 15). Some schedulers add a leading seconds field, making six fields.
Reading an example
*/15 * * * * runs every 15 minutes. 0 0 * * * runs daily at midnight. 30 8 1 * * runs at 08:30 on the first of every month. Because the syntax is terse, a cron explainer that translates it into plain English helps avoid mistakes.
FAQ
What does * mean in cron?
An asterisk means 'every' possible value for that field — so * in the hour field means every hour.
How many fields does a cron expression have?
Five in standard Unix cron (minute, hour, day-of-month, month, day-of-week). Some systems add a sixth seconds field.