Cron Expression Explainer

Validate standard 5-field Linux/Kubernetes cron expressions and translate them into human-readable schedules.

5-Field Cron Expression (minute hour day-of-month month day-of-week)

Schedule Breakdown

Upcoming 5 Execution Times (UTC)

Standard 5-Field Cron Syntax Reference

Standard POSIX and Linux cron daemons, GitHub Actions scheduled workflows, and Kubernetes CronJob manifests use five whitespace-separated time fields in the 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).

Four special operators control recurrence patterns: an asterisk (*) matches every valid value for that field; a comma (1,15) specifies a discrete list; a hyphen (1-5) defines an inclusive range such as Monday through Friday; and a slash (*/15) defines step intervals. Combining ranges and steps—such as */15 9-18 * * 1-5—schedules a task every 15 minutes during weekday business hours.

Production tip: Always verify which timezone your scheduler uses. Cloud platforms such as GitHub Actions, AWS EventBridge, and default Kubernetes clusters evaluate cron schedules in UTC, which avoids Daylight Saving Time (DST) skipped or duplicated runs that can affect local-time servers.