Preset schedule
Runs once every minute, expression * * * * * - good for monitoring and heartbeat tasks.
Common templates
Load one into the builder with a click and review its descriptionCron expression
* * * * *
Format is minute hour day month weekday; 0 and 7 both mean Sunday. Abbreviations like JAN-DEC and SUN-SAT are accepted.
Next run times
In the selected time zone, up to the next 10 runs
Run times use the clock of the selected zone (DST handled automatically); a cron expression itself carries no zone - verify against the server TZ when deploying. Output format: minute hour day month weekday.
(invalid expression - no upcoming times)
Paste to parse
Paste an existing cron expression to check its meaning; Apply to builder loads it back into the visual panel aboveFeatures
- Six presets cover the common cases: every minute, every hour, every day, every week and every month - the expression appears instantly.
- Custom mode builds each of the five fields (minute / hour / day / month / weekday) with *, steps */n, ranges a-b, lists a,b,c and English abbreviations like MON / JAN.
- Live validation flags out-of-range values and syntax errors per field, and a plain-language description of the schedule updates below.
- The next 10 run times are previewed in your local time zone, so you can confirm the schedule before deploying it.
- One-click copy; your configuration is remembered in the browser for the next visit.
- 100% in-browser: nothing is uploaded, and the UI supports 简体 / 繁體 / English.
How to use
- Every day at 08:30: pick the Every-day preset, set hour 8 and minute 30 - you get 30 8 * * *.
- Weekdays at 09:00: pick Every week, select Mon-Fri, hour 9 and minute 0 to get 0 9 * * 1-5.
- For intervals such as every 10 minutes or every 3 hours from 02:00, switch to Custom and set the field to a step like */10 or 2-23/3.
- Check the Next run times list, click Copy, then paste the expression into crontab, Quartz or your cloud scheduler.
FAQ
- What do the five fields mean?
- They are minute (0-59), hour (0-23), day of month (1-31), month (1-12) and weekday (0-7, where 0 and 7 both mean Sunday). Both Linux crontab and Quartz use this order; note that Quartz also has a 6th seconds field - this tool emits the standard 5-field form, and you can append 0 or * if you need second-level schedules.
- How do steps like */5 and ranges like 10-20 work?
- */n takes every n-th value starting from the smallest allowed (so */5 means 0,5,10,...,55); a-b takes every value in the closed range; a-b/n steps by n from a to b. Combine any of these with commas, e.g. 0,15,30,45 or 1-5,10-20. The Custom mode buttons generate all of them for you.
- What happens when both day and weekday are restricted?
- In standard 5-field cron, day-of-month and weekday follow classic Vixie semantics: if both fields are *, every day matches; if one is *, only the other restricts the schedule; only when both fields are restricted do they OR together (the job runs when either matches). For example 0 12 13 * 5 runs at 12:00 both on the 13th of every month and on every Friday, while 0 12 * * 5 runs only on Fridays. If you need AND semantics (e.g. the 13th when it is also a Friday), add that check in your program or use Quartz's ? syntax - this tool follows the classic crontab semantics.
- Which time zone are the next run times in?
- Your device's current local time zone. A cron expression carries no time-zone information; the actual schedule on a server follows that server's TZ setting, so when deploying across time zones verify the trigger times against the server's zone.
- Are my expressions stored or uploaded?
- No. Parsing, validation, description and time computation all happen in your browser. This page is fully static with no backend; the only persistence is your own localStorage so the settings can be restored next time. The server never sees your input.
About this tool
This cron expression generator turns common scheduling needs into a visual panel: presets for minute/hour/day/week/month granularity, plus a custom mode supporting *, steps, ranges, lists and abbreviations. It shows a plain-language description and the next 10 trigger times as you build, so you never ship a cron that fires at the wrong moment.
Everything is implemented in browser-side JavaScript with standard 5-field semantics (day and weekday are OR-ed as in classic crontab). No backend, no third-party APIs, and the UI supports 简体 / 繁體 / English.
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Runs entirely in your browser · Standard 5-field cron · Free · 中文 / 繁體 / English