A tool for figuring out when a cron expression like `*/5 9-17 * * 1-5` from your crontab will actually fire. Paste an expression and it translates each field — minute, hour, day-of-month, month, day-of-week — into plain language, then lists the next run times in your device's local time. It handles the standard five fields (minute hour day month weekday), an optional leading seconds field (six fields), names such as `JAN`–`DEC` and `MON`–`SUN`, and aliases like `@daily`, `@hourly`, `@weekly`, `@monthly`, `@yearly`, and `@midnight`. It understands `*` (every), `*/15` (every 15), `1-5` (ranges), `0,30` (lists), and `9-17/2` (range with step). The "Summary" condenses the whole expression into one line, while the "Breakdown" table shows each field's raw value next to its meaning. When both day-of-month and day-of-week are restricted, the next-run calculation uses the classic Vixie cron rule of matching either one (OR). You can show between 1 and 20 upcoming runs, and that choice is saved in your browser so it opens the same way next time. Importantly, the cron expression you enter is never uploaded, stored, or sent to a server — all parsing and time calculation happen with JavaScript's Date entirely inside your browser, so it is safe to paste internal job definitions. Note that Quartz-specific tokens `L` (last), `W` (weekday), and `#` (nth weekday) are out of scope, and expressions using them are flagged as errors. Because cron is easy to get wrong around seconds and weekday numbering (both 0 and 7 mean Sunday), always confirm the result against the listed next run times.