Cron Expression Builder
Build, validate, and preview cron schedules — with next-run times and plain-English explanations.
100% in your browser. Nothing is uploaded.
Presets
0–59
0–23
1–31
1–12 or jan–dec
0–6 or sun–sat
At 09:00 on Monday, Tuesday, Wednesday, Thursday, Friday.
Next 5 scheduled runs
- 1 6/5/2026, 9:00:00 AM
- 2 6/8/2026, 9:00:00 AM
- 3 6/9/2026, 9:00:00 AM
- 4 6/10/2026, 9:00:00 AM
- 5 6/11/2026, 9:00:00 AM
Frequently asked questions
Is my cron expression sent to a server?
No. All parsing, validation, and next-run calculation happens entirely in your browser. Nothing is sent to a server — not even a single character of your expression.
What syntax does this support?
Standard five-field cron: minute, hour, day-of-month, month, and day-of-week. Supports wildcards (*), step values (*/n), ranges (a-b), range steps (a-b/n), comma lists, and common name aliases for months (jan–dec) and weekdays (sun–sat).
Why do day-of-month and day-of-week interact oddly?
Standard cron OR semantics: when both fields are restricted (neither is *), a run is scheduled if either matches. This matches the behavior of most Unix cron implementations.
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