Cron Job Generator

How to Use the Cron Job Generator

Each row in the form represents one of the five fields in a standard cron expression. For every field, choose a mode: "Every" produces a wildcard, "Every Nth" produces a step value like */5, and "Specific" lets you enter exact values or comma-separated lists. For months and days of the week, checkboxes let you pick individual values by name instead of remembering numbers. Click "Build" and the tool assembles your choices into a valid cron expression, displays what it means in plain English, and calculates the next five times the schedule would fire.

The preset buttons at the top load common schedules with a single click. Use them as starting points, then adjust individual fields to match your exact needs. The result updates only when you click Build, so you can make multiple changes before generating the final expression.

Understanding the Five Cron Fields

A cron expression reads left to right as minute, hour, day of month, month, day of week. The minute field accepts 0 through 59. The hour field uses a 24-hour clock from 0 to 23, where 0 is midnight and 13 is 1 PM. The day of month field ranges from 1 to 31. The month field counts from 1 for January through 12 for December. The day of week field runs from 0 for Sunday to 6 for Saturday, though some systems also accept 7 as Sunday.

Wildcards, Steps, Ranges, and Lists

The asterisk wildcard means every possible value for that field. Step values like */10 in the minute field mean every 10th minute starting from zero: 0, 10, 20, 30, 40, 50. Ranges like 9-17 in the hour field mean every hour from 9 AM through 5 PM. Lists like 1,3,5 in the day of week field mean Monday, Wednesday, and Friday. You can combine ranges and steps: 1-30/5 means every 5th value from 1 through 30.

Common Scheduling Patterns

A daily backup at 2:30 AM is 30 2 * * *. A weekly report every Monday at 9 AM is 0 9 * * 1. A task that runs every weekday at 8 AM is 0 8 * * 1-5 or equivalently 0 8 * * 1,2,3,4,5. Quarterly execution on the first day of January, April, July, and October at midnight is 0 0 1 1,4,7,10 *. A health check every 30 seconds is not possible with standard cron since the smallest unit is one minute.

Where Cron Expressions Are Used

Beyond the traditional Unix crontab, cron expressions appear in Kubernetes CronJob manifests, GitHub Actions workflow schedules, AWS EventBridge rules, Google Cloud Scheduler, Azure Functions timer triggers, Sidekiq, Hangfire, Quartz, and most web framework task schedulers. The five-field format supported by this tool is the most widely compatible. Some systems extend it with a seconds field at the beginning or a year field at the end, but those are non-standard and should be checked against the target platform's documentation.

Frequently Asked Questions

What is a cron expression?

A string of five fields (minute, hour, day of month, month, day of week) that defines a recurring schedule. Each field uses wildcards, specific values, ranges, lists, or step values.

How do I use this generator?

Pick a mode for each field, enter values or check boxes, and click Build. The tool shows the cron expression, a plain-English description, and the next 5 scheduled run times.

What does */5 mean?

Every 5th value from the minimum of the field's range. In the minute field: 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55. In the hour field: 0, 5, 10, 15, 20.

Can I select multiple days or months?

Yes. Switch the field to Specific mode and check the values you want. They combine into a comma-separated list in the cron expression.

Where can I use the generated expression?

In Unix crontab, Kubernetes CronJobs, GitHub Actions, AWS EventBridge, Google Cloud Scheduler, CI/CD pipelines, and most scheduling libraries in any language.