Cron Expression Next Run Calculator
Decode any standard 5-field cron expression and see exactly when it will fire next.
How does this calculator work?
Enter a standard 5-field cron expression and a start date, and this tool expands each field, applies the day-of-month/day-of-week rule, and lists the next several exact run times. It also generates a plain-English description and an approximate frequency so you can verify any crontab schedule at a glance.
Formula
How this is calculated
A cron expression has five space-separated fields: minute (0-59), hour (0-23), day-of-month (1-31), month (1-12), and day-of-week (0-7, where both 0 and 7 mean Sunday). Each field is expanded into a set of allowed values, supporting "*" (all), ranges like "9-17", step values like "*/15" or "0-30/10", and comma lists like "1,15,30".
To find runs, the calculator starts at the supplied start date plus the chosen start hour and minute, then walks forward one minute at a time. A given minute is a match when its minute, hour, and month all belong to their allowed sets and the day rule holds. Following standard crontab semantics, when both the day-of-month and day-of-week fields are restricted the minute matches if EITHER one matches; if only one is restricted, only that field must match; if both are "*", any day qualifies.
The first N matching minutes (1-20) are reported as concrete local timestamps, alongside an auto-generated plain-English description and an approximate frequency derived from the gap between the first two runs. Times are computed in the browser local time zone, and the search scans up to roughly four years ahead to catch rare schedules such as February 29.
Frequently asked questions
In order: minute, hour, day-of-month, month, and day-of-week. Day-of-week accepts 0-7 where 0 and 7 both represent Sunday.
Per the POSIX cron rule, when both fields are restricted the schedule fires if either condition matches. If only one is set, just that one must match.
Standard 5-field cron: asterisks, ranges (9-17), steps (*/15 or 5-50/5), and comma lists (1,15,45). Named values like MON or JAN and special strings like @daily are not parsed.
Also known as
TG we-Calculate Editorial Team. (2026). Cron Expression Next Run Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/cron-expression-next-run-calculator
TG we-Calculate Editorial Team. "Cron Expression Next Run Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/cron-expression-next-run-calculator.
TG we-Calculate Editorial Team, "Cron Expression Next Run Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/cron-expression-next-run-calculator
@misc{wecalculate_cron_expression_next_run_calculator, title = {Cron Expression Next Run Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/cron-expression-next-run-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?