⏰ Cron Expression Tester
Test cron expressions and see next execution times with syntax validation
Understanding Cron Expressions
What is Cron?
Cron is a time-based job scheduler in Unix-like operating systems. Cron expressions define schedules using 5 fields: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6, where 0 is Sunday). These expressions allow you to schedule tasks to run automatically at specific times.
Special Characters
Asterisk (*) means "every" - e.g., * in the hour field means every hour. Comma (,) lists multiple values - e.g., 1,15 means the 1st and 15th. Dash (-) specifies ranges - e.g., 1-5 means 1 through 5. Slash (/) specifies intervals - e.g., */5 means every 5 units.
Common Use Cases
Cron is used for automated backups, log rotation, sending scheduled emails, database maintenance, clearing caches, and running batch jobs. It's essential for system administration and automation tasks that need to run on a regular schedule.
How to Use This Tool
- Type your cron expression in the format: minute hour day month weekday (e.g., 0 12 * * * for daily at noon)
- Optionally click one of the preset buttons for common cron expressions like hourly, daily, or weekly schedules
- View the breakdown of each field (minute, hour, day, month, weekday) with clear descriptions of what each means
- Read the human-readable description to understand in plain English when the cron job will run
- Review the next 10 scheduled execution times to verify the cron expression works exactly as you expect
Cron Expression Format
| Field | Allowed Values | Special Characters |
|---|---|---|
| Minute | 0-59 | * , - / |
| Hour | 0-23 | * , - / |
| Day | 1-31 | * , - / |
| Month | 1-12 | * , - / |
| Weekday | 0-6 (Sun-Sat) | * , - / |
Frequently Asked Questions
What is a cron expression?
A cron expression is a string of 5 fields (minute hour day month weekday) that defines a schedule for automated tasks in Unix-like systems. Each field can contain specific values, ranges, or wildcards.
What do the asterisks (*) mean in cron?
An asterisk (*) in a cron expression means 'every' or 'any'. For example, * in the hour field means every hour, and * in the minute field means every minute.
How do I schedule a job to run daily?
To run daily at midnight, use: 0 0 * * *. To run daily at a specific time like 3:30 PM, use: 30 15 * * *. The first number is minutes, the second is hours (in 24-hour format).
Is this tool free to use?
Yes, this cron expression tester is completely free to use with no registration or limitations.
Does this work on mobile devices?
Yes, this tool is fully responsive and works on all mobile devices, tablets, and desktop computers.