View future cron matches in a calendar
Showing next 1000 cron schedules
0 0 31 2 * parses fine but never fires (Feb 31 doesn't exist). The calendar will be blank.0 0 29 2 * fires only on leap-year Februaries. The calendar may show only one match in the next 365 days.* * * * * fires every minute. The calendar shows the next 30 minutes.0 0 31 * * fires only in months with a 31st (Jan, Mar, May, Jul, Aug, Oct, Dec). Spot the gaps in February, April, June, September, November.All three confirm a cron is “correct”, but they answer different questions. The cron tester answers “is the syntax valid?”. The cron evaluator answers “when will it actually run?”. The cron debugger answers “why isn't it running when I expect?”. In practice you use whichever framing feels closest to the question in your head.
Paste the cron and CronTool evaluates the next 30+ runs against a calendar, plus a plain-English description and field validation. 'Evaluate' here means computing what the expression will actually do, not just whether it parses.
By default the evaluator starts from now. To check what the cron would do from a specific moment (e.g. a year ago, or a future date), edit the expression and the calendar updates instantly. For programmatic evaluation from arbitrary dates, use the underlying matcher library — the package CronTool wraps lets you pass `startAt`.
The evaluator uses the same parser+matcher used by production schedulers. The next-runs calculation is deterministic — same input, same output. Edge cases like Feb 29, daylight saving, and L/W modifiers are handled. The only thing the evaluator can't predict: actual execution drift caused by host load, scheduler queueing, or downstream dependencies.
Yes — use the multi-cron visualizer. Add as many cron expressions as you want and CronTool plots all their runs on a single calendar. Color-code each cron to make overlaps obvious.
Ready to schedule it?
WordPress, Shopify, Railway, Cloud Run, Vercel, HubSpot, Ghost, your own box. If it answers HTTP, Crontap can drive it on a clock you can read, in the timezone that actually matters, and page you when something breaks.
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Schedule
“every 5 minutes”
Next run
in 23s