Cron expression explainer

Paste a 5-field cron expression. We explain it in plain English and show the next 6 fire times in UTC. Catches the day-of-week OR day-of-month quirk most builders trip on.

Cron expression

Explanation

Valid

at minute 0, hour 9, every day-of-month, every month, on MON, TUE, WED, THU, FRI (UTC).

Minute

Hour

Day-of-month

1, 2, 3, 4, 5… (31 total)

Month

Jan, Feb, Mar, Apr, May… (12 total)

Day-of-week

Mon, Tue, Wed, Thu, Fri

Next 6 fire times

#1 2026-08-13 (Thu) 09:00 UTC
#2 2026-08-14 (Fri) 09:00 UTC
#3 2026-08-17 (Mon) 09:00 UTC
#4 2026-08-18 (Tue) 09:00 UTC
#5 2026-08-19 (Wed) 09:00 UTC
#6 2026-08-20 (Thu) 09:00 UTC

The famous gotcha: when both day-of-month and day-of-week are restricted (neither is *), cron fires when either matches, not both. So 0 0 1 * 0 fires on the 1st of every month ORevery Sunday — not just on the 1st when it's a Sunday. We've seen this break a lot of backup schedules. All times are UTC.

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