Cron Expression Parser

Parse cron expressions to calculate next execution times and convert to human-readable format.

Cron Expression
Minute
Hour
Day (Month)
Month
Day (Week)
Human Readable
At 00:00 (midnight) every day
Next 5 Executions
Common Presets
Cron Syntax Reference
Format minute hour day(month) month day(week)
* Any value
, Value list separator (e.g., 1,3,5)
- Range of values (e.g., 1-5)
/ Step values (e.g., */5 = every 5)
Minute: 0-59
Hour: 0-23
Day: 1-31
Month: 1-12
Weekday: 0-6 (Sun-Sat)
What is a Cron Expression?

A cron expression is a string consisting of five or six fields that define a schedule for running automated tasks. Originally from Unix cron daemon, this syntax is now used in many scheduling systems. Each field represents a time unit: minute, hour, day of month, month, day of week, and optionally year.

Cron Field Format

Standard cron has 5 fields: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-6, Sunday=0). Special characters include: * (any), , (list), - (range), / (step). Extended formats may include seconds and year fields.

Common Use Cases
  • Scheduling backup jobs
  • Running periodic data synchronization
  • Sending scheduled emails or notifications
  • Clearing temporary files and caches
  • Generating periodic reports
Common Patterns
Input: 0 0 * * *
Output: Every day at midnight
Input: */15 * * * *
Output: Every 15 minutes
Input: 0 9 * * 1-5
Output: Every weekday at 9 AM
Input: 0 0 1 * *
Output: First day of every month at midnight
Frequently Asked Questions

What timezone does cron use?

Traditional cron uses the system timezone. Modern schedulers like Kubernetes CronJobs let you specify the timezone. Always verify which timezone your cron system uses.

How do I run a job every second?

Standard 5-field cron doesn't support seconds (minimum is every minute). Some systems like Quartz support 6-field cron with seconds. Alternatives include using sleep loops or task schedulers designed for sub-minute intervals.