Cron Expression Builder

What is a Cron Expression?

A cron expression is a string of five fields — minute, hour, day-of-month, month, day-of-week — that define a recurring schedule for Unix cron, GitHub Actions, Kubernetes CronJobs, AWS EventBridge, and most CI/CD systems. Each field accepts a specific value, a wildcard (*), a range (1-5), a list (1,3,5), or a step (*/15).

How to Use

1. Builder mode — Set each field using Every / Specific / Range / Step / List controls. A live cron string and explanation update as you type.
2. Parser mode — Paste any existing cron expression to get a plain-English description and the next 5 scheduled run times.
3. Use presets (e.g. Every hour, Every weekday at 9 AM) as a starting point.

Common Cron Mistakes

• Wrong field count — Standard cron has 5 fields. Some systems (AWS, GitHub Actions) add a 6th seconds field at the front — check your platform's docs.
• Day-of-month + day-of-week interaction — When both are non-*, most cron implementations use OR logic (runs if either matches).
• Timezone confusion — Cron runs in the server's local timezone by default. For UTC-pinned schedules, set TZ=UTC or use your platform's timezone setting.

Quartz, Databricks and EventBridge Cron

This builder writes standard 5-field Unix cron. Quartz (used by Databricks jobs) and AWS EventBridge use different formats: a seconds or year field, ? in one day field, and Sunday = 1 instead of 0. A Unix expression pasted into either one is rejected or runs on the wrong days.

• Quartz Cron Generator — validate and explain Quartz expressions, including L, W and #.
• EventBridge Cron Expression Validator — check cron() and rate() expressions with next runs in UTC.
• Cron Converter — convert between Unix, Quartz and EventBridge with a warning for every rule that changes.

FAQs