Cron Next Run Calculator

About this calculator

A cron expression is a compact 5-field schedule format — minute hour day-of-month month day-of-week — used by the Unix/Linux cron daemon, and by extension by CI/CD tools like GitHub Actions and Jenkins, and by Kubernetes CronJobs. Each field accepts a wildcard (* for “every value”), a single number, a range like 1-5, a step like */15, or a comma list like 1,15,30.

Finding the next run means walking forward from a start time and testing each candidate minute against all five fields at once. One quirk carried over from Vixie cron is that when both day-of-month and day-of-week are restricted (not *), a match on either field is enough — they are combined with OR, not AND. This calculator parses the expression, applies that rule, and reports the next fire time along with the minutes remaining until it runs.