What is a Cron Expression?
A cron expression is a powerful scheduling syntax used by Unix-like operating systems to automate recurring tasks. It consists of five fields separated by spaces: minute, hour, day of month, month, and day of week. Each field can contain specific values, ranges, lists, or special characters to define precisely when a job should run. Our cron parser converts these cryptic expressions into human-readable descriptions instantly.
Why Use Our Cron Parser?
- Instant Translation: Convert cron expressions to plain English immediately
- Next Run Times: See the next 5 scheduled execution times at a glance
- Field Breakdown: Understand each part of the expression with allowed ranges
- Validation: Catch syntax errors before deploying to production
- 100% Private: All parsing happens in your browser - no data sent to servers
Cron Expression Format
Standard cron expressions use five fields in this order:
│ ┌───────────── hour (0-23)
│ │ ┌───────────── day of month (1-31)
│ │ │ ┌───────────── month (1-12)
│ │ │ │ ┌───────────── day of week (0-7)
│ │ │ │ │
* * * * *
Common Cron Special Characters
- * (asterisk): Matches any value. "*" in hour means "every hour".
- , (comma): Lists multiple values. "1,15" in day means "1st and 15th".
- - (hyphen): Specifies a range. "1-5" in weekday means "Monday to Friday".
- / (slash): Specifies step values. "*/10" in minute means "every 10 minutes".
Common Cron Expression Examples
0 * * * * - Every hour at minute 0 (hourly)
0 0 * * * - Every day at midnight (daily)
0 9 * * 1-5 - Every weekday at 9:00 AM
*/15 * * * * - Every 15 minutes
0 0 1 * * - First day of every month at midnight
0 0 * * 0 - Every Sunday at midnight (weekly)
Frequently Asked Questions
How do I test if my cron expression is correct?
Enter your expression in our parser and check the human-readable output. If it matches your intended schedule and shows the correct next run times, your expression is correct. Invalid syntax will display an error message.
What's the difference between cron and crontab?
Cron is the daemon (background service) that runs scheduled tasks. Crontab is the file or command used to create, edit, and manage cron jobs. The expressions used in crontab files are called cron expressions.
Can I use this for Kubernetes CronJobs?
Yes! Kubernetes CronJobs use the same 5-field cron expression format. Our parser works perfectly for validating schedules for Kubernetes, AWS CloudWatch Events, GitHub Actions, and other platforms using standard cron syntax.
Why doesn't my cron job run when expected?
Common issues include timezone mismatches (cron uses server time), overlapping day-of-month and day-of-week conditions (OR logic, not AND), and incorrect field order. Use our parser to verify your expression matches your intended schedule.