Cron Expression Builder & Explainer
Understand any cron expression in plain English and preview its next run times — 100% in your browser.
minute · hour · day-of-month · month · day-of-week
About Cron Expression Builder & Explainer
Paste a standard 5-field cron expression (minute, hour, day-of-month, month, day-of-week) and get a readable explanation of when it runs, plus a preview of the next five run times in your local time zone. Ranges (1-5), lists (1,15,30), steps (*/15) and month/weekday names (JAN, MON) are all supported.
Use the presets to start from a common schedule. Everything is computed locally in your browser; nothing is uploaded.
How to use Cron Builder
- Set a five-field cron expression or use the field controls to build it.
- Read the plain-language summary and inspect the next suggested runs before using it in your scheduler.
Limitations and common mistakes
Cron dialects differ: some include seconds or a year, and day-of-month/day-of-week matching rules vary. Confirm the expression against the exact scheduler you deploy.
The scheduler's timezone and daylight-saving behavior determine actual run times. The next-run preview is not a guarantee that a remote job will execute successfully.
The tool processes its input locally on your device. Read our privacy policy for analytics, storage and network details.
Weekday mornings
0 9 * * 1-5
At minute 0 past hour 9, on Monday, Tuesday, Wednesday, Thursday, Friday.
The tool also lists the next five run times for the expression.
Frequently asked questions
What do the five fields mean?
In order: minute (0–59), hour (0–23), day-of-month (1–31), month (1–12) and day-of-week (0–7, where 0 and 7 are Sunday).
Does it support steps, ranges and lists?
Yes — */15 (every 15), 1-5 (a range), 1,15,30 (a list) and combinations, plus month and weekday names like JAN and MON.
How are day-of-month and day-of-week combined?
Following cron convention, when both are restricted the schedule runs when either matches; if only one is set, just that one applies.
Which time zone are the next runs in?
Your browser's local time zone. The calculation runs entirely on your device.
For related tasks, explore Timestamp Converter and HTTP Status Codes. Their guides explain the different inputs, assumptions and output formats.