Developer Tools

Cron Expression Parser

Paste a five-field cron expression (minute hour day-of-month month day-of-week). Invalid ranges are rejected. The next five matching local times are listed using a simple iterator — it does not implement every cron extension (seconds fields, @hourly aliases, or timezone prefixes).

Your workspace

Runs in your browser

Cron expression (minute hour day month weekday)

at minute 0, at hour 9, on Monday through Friday

Next 5 executions (local)

No matches in the next year. Check the fields — some combinations never occur (for example day 31 in February).

How to use

1Enter a 5-field expression or pick a preset.
2Read the explanation.
3Check the next five local times.

What this tool does

— Field validation
— Human-readable summary
— Next five runs

Useful when

— Checking a crontab before deploy
— Teaching cron syntax

Limits

— Standard 5-field cron only (no seconds, no @daily aliases).
— Day-of-month and day-of-week combination follows a simple AND match, which may differ from some cron daemons.

Where processing happens

Parsing and next-run calculation happen in the browser against your local clock.

Questions

Why was minute 99 rejected?+

Minutes must be 0–59. The parser rejects out-of-range fields instead of wrapping them.

Guides for this tool

How to debug JSON, Base64 and cron in your browser
Validate JSON, round-trip Base64 text and check five-field cron syntax using local browser tools.
How to convert a meeting time between cities
Search source and destination IANA zones in your browser. Handle skipped local times and choose between repeated daylight-saving occurrences.
Understanding five-field cron expressions
Minute, hour, day, month, weekday — what ToolNest’s parser supports, and which cron features it does not.