Decode a cron expression and see its next run times.
Parsed locally in your browser.
What does a cron expression mean?
A 5-field cron expression sets 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). Fields support *, ranges (1-5), lists (1,3,5) and steps (*/15). For example, 0 9 * * 1-5 means 09:00 every weekday, Monday to Friday.
Understanding your result
When both day-of-month and day-of-week are restricted, a run fires if either matches — the standard cron behaviour.
Formula and method
Fields are 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). They support *, ranges (1-5), lists (1,3,5) and steps (*/15).
Assumptions and limitations
The helper parses standard five-field cron with *, ranges, lists and steps, and lists upcoming runs in your local timezone. It does not interpret extensions such as named months, day-of-week names, @-shortcuts or a leading seconds field, and cannot account for the specific scheduler, daemon downtime or daylight-saving quirks on your server.
Worked example
0 9 * * 1-5 means 09:00 every weekday (Monday to Friday).
How to use this tool
- Enter a 5-field cron expression.
- Review the field breakdown.
- Check the next run times.
Common mistakes to avoid
- Using 6 fields (with seconds) — standard crontab uses 5 fields.
- Forgetting that day-of-week 0 and 7 both mean Sunday.
About the Cron Expression Helper
Paste a cron expression to see exactly when it runs. The helper breaks down each field and lists the next run times in your local timezone.
Who should use this tool
Developers and sysadmins setting up scheduled jobs (crontab, CI pipelines, schedulers).
Benefits
- Understand any cron field without memorising the syntax
- Preview the next run times before deploying a job
- Catch mistakes that would silently never fire
- See day-of-month and day-of-week overlaps explained clearly
Practical use cases
- Verify a scheduled backup or report runs when expected
- Learn cron syntax while writing your first job
- Debug a task that fired at the wrong time
- Document when a pipeline's cron trigger will next run
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Frequently asked questions
What does */15 mean?
A step value — */15 in the minute field means every 15 minutes.
Which timezone are the run times in?
Your local timezone, as set on your device.
Does this support the seconds field or @daily shortcuts?
This helper reads the standard five-field format: minute, hour, day-of-month, month and day-of-week. It does not parse a leading seconds field or named shortcuts like @daily and @hourly, which some schedulers add. If your system uses those, translate them to the five-field form first.