Cron Schedule Visualizer

Plain-English field descriptions you can verify

The tool breaks the expression into its five fields and renders each one in human terms. A minute field of */15 becomes 'every 15 minutes'; an hour range of 9-17 becomes 'during the hours 09:00, 10:00… 17:00'; a day-of-week list becomes 'on MON, TUE, WED, THU, FRI'. This per-field breakdown is the fastest way to catch the classic mistakes: swapped hour and minute fields, an off-by-one month, or a day-of-week that starts on Sunday when you assumed Monday. The summary sentence at the top composes all fields into a single readable sentence, so 'does this run when I think it does?' becomes a question you answer by reading rather than by running it blind and checking logs at 3 AM. Field names accept both numeric values and three-letter names — JAN-DEC for months, SUN-SAT for weekdays — matching what your crontab editor accepts.

Next-five execution preview in your local timezone

Cron fires in the server's timezone, but you live in yours — which is exactly why '0 0 * * *' produces a 9 AM notification for one colleague and a 3 AM page for another. After parsing, this tool walks the calendar minute-by-minute and lists the next five matching timestamps rendered in your device's local timezone, so you can compare them directly with the meetings, batch windows or backup slots you are scheduling around. The next-run preview also catches expressions that can never fire: a day-of-month of 31 combined with a month list that only contains February produces zero matches, and the tool tells you that plainly instead of letting you discover it after a missed monthly report. For recurring intervals like */15, the five timestamps confirm the cadence; for one-shot patterns like '0 12 1 1 *', they confirm the exact next firing date.

Full syntax support with Vixie day/dow semantics

The parser supports the complete standard crontab grammar: asterisks, comma-separated lists, hyphenated ranges, slash steps (both */n and range/n), and month or weekday names. It also implements the subtle Vixie cron rule that trips up even senior engineers: when both day-of-month and day-of-week are restricted, a day matching EITHER condition runs — they are OR-ed, not AND-ed. '0 0 1 * MON' fires on the first of every month AND every Monday, not on Mondays that happen to be the first. Most hand-rolled parsers get this wrong, which is why schedules behave differently once they reach the real crontab. Here, the field table labels wildcard fields explicitly, so you can see which constraint is active. Values are range-checked — minute 75 or month 13 produce friendly errors naming the offending field — instead of the silent misfires you get from regex-only validators.

Common cron patterns as one-click presets

Most schedules people need are already patterns: every fifteen minutes during business hours, nightly at 2 AM, every Monday at 9, the first of each month at midnight, every six hours around the clock. The preset selector loads these and other battle-tested expressions so you can start from a known-good baseline and adjust fields visually instead of composing from scratch. Each preset demonstrates a different syntax feature — steps, ranges, weekday names, month restrictions — which makes the tool a practical tutorial for the syntax itself. Once the expression behaves the way you want, copy it straight into your crontab, Kubernetes manifest, GitHub Actions schedule key or monitoring system. Since parsing and simulation happen entirely in the browser, it is equally safe to paste expressions from a private scheduler and to use the tool as documentation during code review — the expression never leaves your machine.

Step by step: how to use Cron Visualizer

1. 1

   Paste your five-field cron expression into the input — or click 'Try an example' to load a realistic production schedule.

2. 2

   Read the plain-English summary at the top and the per-field breakdown underneath it to verify each field means what you intended.

3. 3

   Check the syntax checklist: the tool highlights which fields are wildcards, which are restricted, and flags out-of-range values with line-level messages.

4. 4

   Review the next five execution timestamps in your local timezone — confirm they align with the windows you are scheduling around.

5. 5

   Adjust fields as needed; the description and next runs update live as you edit.

6. 6

   Copy the final expression into your crontab, Kubernetes CronJob, CI schedule or monitoring platform.

Frequently asked questions