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Cron expression explainer
Paste a cron expression to read it in plain English and see the next eight times it will run, in UTC or your own time zone. It follows standard five-field cron, as used by Linux crontabs, Kubernetes CronJobs, and GitHub Actions schedules.
minute hour day-of-month month day-of-week
At 09:30, on Monday through Friday.
Next runs (UTC)
Cron uses the server’s time zone. GitHub Actions schedules run in UTC; Kubernetes CronJobs use the controller’s time zone unless spec.timeZone is set.
Runs entirely in your browser. Nothing you enter is sent to Shortspan or saved, and no account is needed.
Next step
Scheduled jobs need credentials too
A cron job usually needs a database password or API key. With Shortspan, the job runs under shortspan run with a scoped token, and the secrets arrive in its environment at run time instead of sitting in the crontab or a file beside it.
The five fields
Minute (0–59), hour (0–23), day of month (1–31), month (1–12 or JAN–DEC), and day of week (0–7 or SUN–SAT, where both 0 and 7 are Sunday). Each field takes *, a value, a range such as 1-5, a list such as 1,15, or a step such as */15. Shortcuts such as @daily and @hourly are expanded.
The day rule
When both day of month and day of week are restricted, cron runs on days that match either one - 0 0 13 * 5 runs on the 13th and on every Friday, not only on Friday the 13th. If either field starts with *, both must match. The explainer applies this rule and says when it is in play.
Common questions
- What time zone does cron use?
- A crontab runs in the server’s time zone. GitHub Actions schedules run in UTC. Kubernetes CronJobs use the controller’s time zone unless
spec.timeZoneis set. - Why is my six-field expression rejected?
- A leading seconds field, and the
?,L,W, and#characters, belong to Quartz and Spring scheduling, not standard cron. - Does `*/5` start at zero?
- Yes:
*/5in the minute field means 0, 5, 10 and so on. To offset it, write2/5or2-59/5.
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