Cron Parser

Why You'd Want This

Cron syntax is one of those things everyone half-remembers. Five fields, asterisks everywhere, and a nagging suspicion that 0 0 * * 1 might mean Monday or might mean the 1st. Getting it wrong is cheap to type and expensive to discover — a backup job that runs every minute instead of every midnight, or a report that silently never fires. This parser translates any expression into a plain-English sentence and, more importantly, shows you the next ten actual run times. If the list doesn't look like what you intended, you've caught the bug before deploying it.

How to Use It

Type or paste an expression into the input — everything updates as you type. The five boxes below break the expression into its fields (minute, hour, day, month, weekday) and highlight the ones that are constrained. The green banner gives you the human-readable description, and the run-time list shows the next ten executions with relative times like "in 12 min". Not sure where to start? Click a preset like Weekdays at 9am and edit from there. Shorthand aliases work too: @daily, @hourly, @weekly, @monthly, and @yearly all expand to their five-field equivalents. The timezone selector controls how the run times are displayed, which helps when your server runs in UTC and your brain runs in local time.

Frequently Asked Questions

Is Sunday 0 or 7?

Here, Sunday is 0 and Saturday is 6. Some cron implementations also accept 7 for Sunday, but 0 works everywhere, so that's what this tool validates against.

What happens if I set both day-of-month and weekday?

They combine with OR, matching classic cron behavior. 0 0 1 * 1 runs at midnight on the 1st of the month and on every Monday — not only when the 1st happens to be a Monday. This trips up almost everyone at least once, and the run-time preview is the quickest way to see it in action.

Why did I get a non-standard notation warning?

The N/S start/step form (like 5/10 for "every 10 minutes starting at minute 5") isn't part of POSIX cron. It works in Quartz, AWS EventBridge, and Spring, but a plain Linux crontab may reject it. The warning appears so you don't paste a Quartz expression into a crontab and wonder why nothing runs.

Does my expression leave the browser?

No. Parsing, description, and run-time calculation all happen client-side. There's no server involved at all.