Cron Expression Parser
Parse a cron expression into a plain-language description and preview the next several run times. Supports the standard 5-field format and the 6-field extended format with seconds.
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How to Use
- Enter a cron expression in the input box, such as 0 0 * * 1-5 (midnight, Monday through Friday).
- The tool parses it live and explains what the expression means.
- Below that it lists the next 5 to 10 run times so you can verify the schedule.
- If the expression is invalid, the tool points out where the problem is and why.
- Click one of the common examples to fill in a preset expression instantly.
Features
- Supports the standard 5-field cron format (minute, hour, day of month, month, day of week).
- Supports the 6-field extended format that includes a seconds field.
- Translates the expression into a natural-language description.
- Previews the next N run times.
- Provides common cron templates for every minute, hour, day, week, and so on.
Use Cases
Debugging scheduled jobs
When setting up scheduled backups or log cleanup on a server, confirm the cron expression fires exactly when you expect.
Learning cron syntax
Work through the common templates and their explanations to pick up cron syntax without digging through the manual.
Configuring CI/CD pipelines
When setting up scheduled triggers in Jenkins or GitHub Actions, verify that the cron expression matches your release plan.
Planning across time zones
Use the run-time preview to check how a schedule in your local time maps to the server's UTC time so a time zone offset does not fire the job at the wrong moment.
FAQ
How many fields does a cron expression have?
Standard Linux cron uses 5 fields (minute, hour, day of month, month, day of week), while frameworks such as Spring extend it to 6 by adding seconds at the front. This tool supports both.
What is the difference between * and ?
An asterisk means any value, while a question mark means no specific value. The question mark is typically used when the day-of-month and day-of-week fields would conflict and one of them must be left unspecified. Standard Unix cron generally does not support ?, but Spring cron does.
How do I run something every 5 minutes?
Use */5 * * * *, where */5 means every 5 minutes, so the whole expression fires at minutes 0, 5, 10, and so on through 55 of every hour.
What does 0 0 1,15 * * mean?
It runs at midnight (00:00) on the 1st and the 15th of every month. A comma separates an enumerated list of values.