Question 1

What format of cron expression does this support?

Accepted Answer

Standard 5-field cron: minute, hour, day-of-month, month, and day-of-week, supporting *, ranges (1-5), steps (*/15), lists (1,15,30), and named months/weekdays. Quartz-style 6/7-field expressions with a seconds or year field aren't supported.

Question 2

Why does my cron run on days that don't match both my day-of-month AND day-of-week rule?

Accepted Answer

This is standard, intentional cron behavior: when both the day-of-month and day-of-week fields are restricted (not "*"), a day matches if EITHER condition is true — it's an OR, not an AND. This tool flags it explicitly whenever it applies to your expression.

Question 3

Are the 'next run' times real or estimated?

Accepted Answer

They're computed exactly — the tool walks minute-by-minute from right now and checks each one against your parsed expression, the same logic a real cron daemon uses, rather than guessing from a pattern.

Cron Expression Explainer

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