Question 1

What is a cron expression?

Accepted Answer

A cron expression is a string of 5 fields (minute hour day-of-month month day-of-week) that defines a recurring schedule. Common systems include cron (Linux), Kubernetes CronJob, Quartz, AWS EventBridge, and Spring Scheduler.

Question 2

How many fields does a cron expression have?

Accepted Answer

Standard cron has 5 fields. Quartz extends it to 6 or 7 fields by adding seconds and optionally a year. This tool supports the standard 5-field format.

Question 3

What does * mean in cron?

Accepted Answer

An asterisk means every possible value of that field. For example, * * * * * runs every minute, while 0 * * * * runs at minute 0 of every hour.

Question 4

What does 0 9 * * 1-5 mean?

Accepted Answer

It means at 09:00 on every weekday from Monday to Friday. Field 5 (day-of-week) 1-5 specifies Monday through Friday.

⏰ Cron Generator & Explainer

Cron Expression 5 fields

Generator (Build with UI)

Common Presets

Cron Expression 5 fields

Generator (Build with UI)

Common Presets

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