🕒 Cron Expression Parser
Validate and understand cron expressions. Supports both 5-field (standard) and 6-field (with seconds) formats.
| Symbol | Meaning | Example |
|---|---|---|
* | Any value | * * * * * = every minute |
*/n | Every n units | */15 * * * * = every 15 minutes |
n-m | Range | 0 9-17 * * * = 9 AM to 5 PM |
n,m | List | 0 0 1,15 * * = 1st and 15th |
? | No specific value | Used for day-of-month or day-of-week |
Common Examples
0 * * * *— Every hour at minute 00 0 * * *— Every day at midnight0 9 * * 1-5— Weekdays at 9 AM*/5 * * * *— Every 5 minutes0 0 1 * *— First day of every month at midnight
What Is a Cron Expression?
A cron expression is a string of five (or six) fields that defines a schedule for recurring tasks.
Originally developed for the Unix cron daemon in the 1970s, cron expressions are now
used across virtually every platform: Linux crontabs, Windows Task Scheduler, cloud services
(AWS CloudWatch, Azure Functions), CI/CD pipelines, and job scheduling frameworks like Quartz.NET
and Hangfire.
Cron Expression Format
A standard cron expression has five fields separated by spaces:
┌───────────── minute (0-59)
│ ┌───────────── hour (0-23)
│ │ ┌───────────── day of month (1-31)
│ │ │ ┌───────────── month (1-12)
│ │ │ │ ┌───────────── day of week (0-7, where 0 and 7 = Sunday)
│ │ │ │ │
* * * * *Special Characters
| Character | Meaning | Example |
|---|---|---|
* | Any value | * * * * * = every minute |
, | Value list | 1,15 * * * * = minute 1 and 15 |
- | Range | 1-5 * * * * = minutes 1 through 5 |
/ | Step values | */10 * * * * = every 10 minutes |
Common Use Cases
- Database Backups: Schedule nightly backups at 2 AM (
0 2 * * *). - Log Rotation: Rotate logs every Sunday at midnight (
0 0 * * 0). - Health Checks: Run system health checks every 5 minutes (
*/5 * * * *). - Report Generation: Generate weekly reports every Monday at 9 AM (
0 9 * * 1). - Cache Invalidation: Clear expired cache entries every hour (
0 * * * *). - Cloud Functions: Trigger serverless functions on a schedule using cron in AWS, Azure, or GCP.
How to Use This Tool
- Enter a cron expression in the input field (e.g.,
*/5 * * * *). - View the human-readable description of the schedule.
- See the next scheduled execution times.
- Modify the expression and see results update instantly.
Why Use This Tool?
- Understand complex cron expressions at a glance.
- Preview upcoming execution times before deploying.
- Supports standard 5-field and extended 6-field cron formats.
- Invaluable for DevOps, CI/CD pipelines, and scheduled tasks.
Frequently Asked Questions
What is the difference between 5-field and 6-field cron?
Standard Unix cron uses 5 fields (minute through day-of-week). Some systems like Quartz add a sixth field for seconds, and some cloud platforms add a year field. This tool supports the standard 5-field format.
How do I run a job every N minutes?
Use the step syntax: */N * * * *. For example, */15 * * * * runs every 15 minutes.