Crontab Expression Explainer

Confirm a cron schedule matches your intent before deploying. Includes the day/weekday OR rule of standard cron.

Crontab Expression Explainer

Explains a cron expression in plain words and shows the next three run times.

Expression (min hour day month weekday)

Minute: 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 Hour: every hour Day: every day Month: every month Weekday: every weekday Next runs: 7/29/2026, 3:20:00 PM 7/29/2026, 3:25:00 PM 7/29/2026, 3:30:00 PM

Easy-to-Misread cron Examples

These results use standard five-field cron semantics. Exact next-run timestamps vary by browser timezone, so the stable field interpretation is recorded here.

Weekdays at 09:00

Example: 0 9 * * 1-5
Result: minute 0 · hour 9 · Monday through Friday

A server configured for UTC will not run this at 09:00 Korean time without an offset.

Day/weekday OR behavior

Example: 0 4 1 * 1
Result: 04:00 on every Monday or every first day of a month

This does not mean only Mondays that are also the first. Standard cron matches either restricted field.

Common Expressions to Copy

Before checking with the explainer, a few patterns are worth memorizing. Note that both 0 and 7 mean Sunday.

*/5 * * * *    every 5 minutes
0 * * * *      top of every hour
0 4 * * *      4:00 AM daily
0 9 * * 1-5    9:00 AM on weekdays (Mon-Fri)
30 2 1 * *     02:30 on the 1st of each month
0 0 * * 0      midnight every Sunday  (0 = Sunday)

Crontab Expression Explainer