Cron Expression Syntax Guide
Master cron expression syntax with clear explanations of every field and operator. Test expressions live in your browser — no crontab access required.
Cron Expression Parser
Parse cron expressions into human-readable descriptions with next scheduled runs. Updates as you type.
Field Breakdown
Next 5 Runs
Cron Syntax Reference
│ ┌───── hour (0-23)
│ │ ┌───── day of month (1-31)
│ │ │ ┌───── month (1-12 or JAN-DEC)
│ │ │ │ ┌───── day of week (0-6 or SUN-SAT)
* * * * *
*any value,list-range/step- Month names (JAN-DEC) and day names (SUN-SAT) are supported.
- Use the Crontab Generator to build expressions visually.
- Everything runs in your browser — no data is sent over the network.
What is a cron expression?
A cron expression is a string of five (or six) fields that defines a recurring schedule. The standard five fields are: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7, where 0 and 7 are Sunday). Special characters include * (any value), , (list), - (range), and / (step). For example, */15 * * * * runs every 15 minutes.
Common use cases
Cron expressions schedule automated backups, log rotation, report generation, database maintenance, email digests, and deployment pipelines. They are used in Unix crontab, Kubernetes CronJobs, GitHub Actions, AWS EventBridge, and CI/CD platforms. Understanding the syntax is essential for any developer working with scheduled automation.
Frequently Asked Questions
What does the asterisk (*) mean in a cron expression?
The asterisk means 'every possible value' for that field. For example, * in the hour field means every hour. Combined with other fields, * * * * * runs every minute of every hour of every day.
How do I run a cron job every 5 minutes?
Use the expression */5 * * * *. The /5 is a step value meaning 'every 5th minute.' This is equivalent to writing 0,5,10,15,20,25,30,35,40,45,50,55 in the minute field.
Related Inspect Tools
Chmod Calculator
Calculate Unix file permissions with an interactive permission matrix
JSON Path Tester
Test JSONPath expressions against JSON data with real-time evaluation
Color Contrast Checker
Check WCAG 2.1 color contrast ratios for AA and AAA accessibility compliance
JSON Schema Validator
Validate JSON data against JSON Schema (Draft 07) with detailed error reporting and schema generation