Cron Expression Explainer - Decode Cron Schedules Online
Cron Expression Explainer
Decode Any 5-Field Cron Schedule Instantly
Enter a cron expression and click Explain
Understanding Cron Syntax
Scheduled Jobs
Cron syntax drives scheduled tasks in Linux crontabs, Kubernetes CronJobs, and most CI/CD pipeline schedulers.
Debugging Schedules
Quickly verify what a cron expression actually means before deploying it, avoiding an accidental every-minute job.
Five Fields
Standard cron has five fields: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), and day-of-week (0-6, Sunday=0).
Local Processing
Your schedule never leaves your browser — parsing and next-run calculation happen entirely client-side.
The Day-of-Month / Day-of-Week Gotcha
When both the day-of-month and day-of-week fields are restricted (not *), standard cron treats them as an OR condition, not AND — the job runs if either field matches. For example, 0 0 1 * 0 runs at midnight on the 1st of the month or every Sunday, not only when the 1st happens to fall on a Sunday. This tool implements that exact behavior, and computes the next 5 real run times so you can verify a schedule before deploying it. Note: this tool supports numeric fields with *, lists, ranges, and step values — named months/weekdays (e.g. JAN, MON) are not supported.
Key Takeaways
- Full Syntax Support: Handles wildcards, lists, ranges, and step values (e.g.
*/15). - Correct OR Logic: Matches standard cron's day-of-month / day-of-week behavior exactly.
- Client-Side Only: All parsing happens locally in your browser — no data is ever sent to a server.