Cron Expression Builder

A cron expression is a 5-field string (minute hour day-of-month month day-of-week) that defines a recurring schedule for automated tasks. It is used in Linux crontab, GitHub Actions, AWS EventBridge, Kubernetes CronJobs, Node.js schedulers, and dozens of other systems. This tool generates the expression from human-readable fields and shows the ready-to-copy syntax for the most common platforms.

Field syntax reference

* — every unit. */n — every nth unit (e.g. */15 in the minute field = every 15 minutes). n-m — range (e.g. 1-5 in day-of-week = Monday to Friday). n,m — list (e.g. 1,3,5 = Mon, Wed, Fri). You can combine: 0,30 9-17 * * 1-5 = at :00 and :30 past each hour from 9am to 5pm, weekdays.

Timezone warning

Cron schedules run in the system timezone of the machine or the configured timezone of the service. A cron job set to 0 9 * * * runs at 9am in whatever timezone the server is configured to. AWS EventBridge rules always run in UTC. GitHub Actions always run in UTC. Always specify whether your intended time is UTC or local, and document it in your code.

GitHub Actions uses a 6-field cron with second-level granularity in some contexts, but the standard Actions schedule trigger uses the standard 5-field POSIX format (UTC). GitHub does not guarantee exact execution time — jobs may be delayed by minutes during periods of high runner demand.