Sviluppatore·4 min di lettura·16 ottobre 2026

How to Write a Cron Expression: The Five Fields Explained

Cron schedules look cryptic until you know the five fields. Learn the format, common examples and how to build one with a plain-English preview.

The five fields

A standard cron expression has five fields in this order: minute (0-59), hour (0-23), day of month (1-31), month (1-12) and day of week (0-6, where 0 is Sunday). An asterisk means every value, so "* * * * *" runs every minute.

Common schedules

"*/5 * * * *" runs every 5 minutes. "0 9 * * *" runs every day at 09:00. "0 8 * * 1-5" runs at 08:00 on weekdays. "0 0 1 * *" runs at midnight on the first of each month. A slash sets a step, a dash sets a range and a comma separates a list.

How to build one here

Open the Cron Expression Generator, click a preset such as every day at 9am, then edit any of the five fields. The expression updates as you type, a plain-English line describes it, and a Copy button puts it on your clipboard.

Things to check

The generator produces standard 5-field cron, with no seconds field and no shortcuts like @daily. The plain-English line understands single values, lists, ranges, steps and month and day names, and flags values that are out of range. Symbols used by some schedulers, such as L, W or ?, are not supported. If you restrict both day of month and day of week, most schedulers run the job when either one matches, and cron usually runs in the server time zone, so confirm both in your scheduler documentation.

Apri lo strumento: Generatore espressioni cron