How to Read and Build Cron Expressions
Understand the five cron fields and build reliable schedules for scripts, backups, and recurring jobs.
The five fields
A standard cron expression contains five space-separated fields: minute, hour, day of month, month, and day of week. The command itself comes after those fields in a crontab.
- Minute: 0–59
- Hour: 0–23
- Day of month: 1–31
- Month: 1–12
- Day of week: 0–6, where 0 is Sunday
Common operators
An asterisk means every allowed value. A comma creates a list, a hyphen creates a range, and a slash sets an interval. For example, */15 in the minute field means every 15 minutes.
Useful examples
0 9 * * 1-5 runs at 9:00 AM from Monday through Friday. 0 0 1 * * runs at midnight on the first day of each month. Always confirm the server timezone before relying on a schedule.
Build before you deploy
Use the Cron Builder to select each field, inspect the plain-English explanation, and copy the final expression. Test important jobs in a safe environment before enabling them in production.