Cron Expression
Cron Syntax
| Symbol | Meaning |
|---|---|
| * | Any value |
| , | Value list separator (1,3,5) |
| - | Range of values (1-5) |
| / | Step values (*/15 = every 15) |
Description
Every 5 minutes
Validation
Next Executions
Next 3 runsEnter a cron expression to see execution times
Invalid cron expression
Common Examples
0 0 * * *
Every day at midnight
0 */2 * * *
Every 2 hours
0 9-17 * * 1-5
Hourly 9-5, Mon-Fri
30 4 1,15 * *
4:30 AM on 1st and 15th
0 0 * * 0
Weekly on Sunday
What is a Cron Expression?
A cron expression is a string representing a schedule for recurring tasks. Originally from Unix cron, it's now used in many systems including Kubernetes, GitHub Actions, and cloud schedulers.
The standard format uses 5 fields: minute, hour, day of month, month, and day of week. Each field can contain specific values, ranges, wildcards (*), or step values (*/5).
Frequently Asked Questions
What does * mean in cron?
The asterisk (*) is a wildcard meaning "every possible value" for that field. For example, * in the hour field means "every hour", while * in the day-of-week field means "every day".
How do I run a cron job every 5 minutes?
Use */5 in the minute field: "*/5 * * * *". The /5 is a step value that means "every 5th value". This runs at minutes 0, 5, 10, 15, etc.
What's the difference between 0 and * in cron?
0 is a specific value (e.g., minute 0, or Sunday), while * means all values. "0 * * * *" runs at minute 0 of every hour, but "* * * * *" runs every minute.
Is Sunday 0 or 7 in cron?
In standard cron, Sunday is 0 and Saturday is 6. However, some systems also accept 7 for Sunday. The days go: 0=Sunday, 1=Monday, 2=Tuesday, etc.