Cron expression for every 21 minutes
Run a scheduled job every 21 minutes with Unix cron, AWS EventBridge, Quartz, and Kubernetes CronJobs.
*/21 * * * *Runs every 21 minutes.
Primary dialect: Unix / Linux
Next run examples
Static preview generated for the primary dialect. AWS examples use UTC; other examples use Europe/Berlin for display.
Jun 9, 2026, 11:00 AM
Jun 9, 2026, 11:21 AM
Jun 9, 2026, 11:42 AM
Jun 9, 2026, 12:00 PM
Jun 9, 2026, 12:21 PM
Dialect versions
Unix / Linux
*/21 * * * *Standard Unix/Linux cron expression when this schedule is expressible with five fields.
AWS EventBridge
rate(21 minutes)AWS EventBridge cron schedules are evaluated in UTC. Use rate(...) for simple fixed intervals when possible.
Quartz
0 */21 * * * ?Quartz includes a leading seconds field and supports additional day operators.
Kubernetes
*/21 * * * *Kubernetes CronJobs use standard five-field cron syntax. Non-standard operators require job-level logic.
Variants
Every 10 minutes
*/10 * * * *Runs at minute 0, 10, 20, 30, 40, and 50.
Every 15 minutes
*/15 * * * *Runs every quarter hour.
Weekday interval
*/21 * * * 1-5Runs on weekdays only.
Kubernetes notes
- Kubernetes CronJobs use standard five-field cron syntax.
- "For frequent schedules
- set concurrencyPolicy intentionally so slow jobs do not overlap."
Common mistakes
- "Writing \"21 * * * *\" runs once per hour at minute 21
- not every 21 minutes."
- Forgetting that cron intervals align to clock boundaries rather than deployment time.
FAQ
What is the cron expression for every 21 minutes?
Use `*/21 * * * *` for standard cron when the scheduler supports this syntax.
Can I use this expression in Kubernetes?
Yes, if it is standard five-field cron. AWS and Quartz-only operators need a Kubernetes-safe alternative or application-level date logic.