Cron Expression Parser
Parse cron expressions into human-readable descriptions with next run times.
?Tips
- Use */5 in the minute field to run every 5 minutes.
- Combine ranges and lists: 1-5 (Mon-Fri) or 1,15 (1st and 15th).
- Next run times use your browser local timezone. Cloud schedulers may use UTC.
- This tool uses standard 5-field cron. For 6-field (with seconds), prepend 0.
Understanding Cron Expressions
Cron is a Unix job scheduler. A cron expression has five fields separated by spaces: minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-7, where 0 and 7 are Sunday). A job runs when all five fields match the current time.
Special characters extend expressiveness. Asterisk (*) matches all values. Comma (,) separates specific values. Hyphen (-) defines ranges. Slash (/) defines steps. For example, */15 means every 15 units and 1-5 means Monday through Friday.
Common use cases include database backups (0 2 * * * for 2 AM daily), log rotation (0 0 * * 0 for weekly), cache clearing (0 */6 * * * for every 6 hours), scheduled emails (0 9 * * 1-5 for weekday mornings), and health checks (*/5 * * * * for every 5 minutes).
Cloud platforms (AWS EventBridge, Google Cloud Scheduler, Kubernetes CronJobs) all support cron-like scheduling. Some extend the format with seconds or year fields.
Timezone handling is critical: traditional cron uses the system timezone, but many cloud schedulers use UTC. Account for DST transitions that can cause jobs to skip or double-fire.