Cron Expression Visualizer

All of them. Standard Unix cron is 5 fields (minute hour day month weekday). Spring, AWS EventBridge, and many cloud schedulers use 6 fields (with a leading second). Quartz uses 6-7 fields (with an optional trailing year). The tool auto-detects the field count and also understands @yearly, @monthly, @weekly, @daily, @hourly, and @reboot macros.

The tool uses the browser's Intl API to compute each timezone's offset from UTC and shows the same firing instant in every selected zone's local wall-clock time. For example, "0 9 * * 1-5" in UTC is Mon-Fri 09:00 UTC, which renders as Mon-Fri 01:00 in San Francisco — a classic 'this is actually the middle of the night' discovery.

The tool simulates the next 30 days from now and counts how many times the cron fires on each calendar day (0, 1, or many). Days with dense firing (e.g. every hour = 24 times) get the deepest color, and days with no firing stay blank. This is far more useful than just listing the next run when you need to spot 'why is this also running on weekends' or 'why does this day have 50 runs'.

'*' matches every value. '/' is a step, so '*/5' means every 5 units. '-' is a range, so '1-5' means 1 through 5. ',' lists multiple values, so '1,3,5' means 1, 3, and 5. The tool explains each field in plain English so you don't have to memorize the syntax.

Yes, the Quartz extensions are supported: L (last day of month), W (nearest weekday), and # (the Nth weekday of the month). These work correctly if your scheduler is Spring, Quartz, or AWS EventBridge.