How to use

Use this when you’re working with Java schedulers (Quartz / Spring) and want quick validation.

Paste your cron expression.
Select Auto (recommended) or force a format.
Enable Strict Quartz if you want the common rule: exactly one of Day-of-Month or Day-of-Week must be ?.
Click Validate to see detected format, normalized expression, and any errors/warnings.

FAQ

What cron format does Java Quartz use?

Quartz typically uses 6 fields (seconds + 5) and optionally a 7th field for year.

Why does Quartz cron use '?' in day-of-month or day-of-week?

? means “no specific value” and is used so you can specify either day-of-month or day-of-week without conflicting.

Does Spring @Scheduled use 5 or 6 fields?

Spring cron commonly uses 6 fields (with seconds). Some environments/docs show 5-field UNIX cron, so confirm your scheduler.

What do 'L', 'W', and '#' mean in Quartz?

L is “last”, W targets the nearest weekday, and # selects the nth weekday of the month (e.g., MON#2).

Can this tool show the next run times?

No—this tool focuses on syntax/format validation and a field breakdown, not computing future fire times.

How strict is the validation here?

It checks field counts, numeric ranges, lists/ranges/steps, and common Quartz rules; exact behavior can still vary by scheduler version/config.

Is Sunday 0 or 1 in day-of-week?

UNIX cron often uses 0 (or 7) for Sunday; Quartz usually uses 1-7. If you use 0 in Quartz, treat it as scheduler-specific.