How This Cron Next Run Calculator Works
Type a cron expression and this cron next run calculator, a genuine crontab next run calculator and cron expression scheduler tool, instantly lists the upcoming timestamps it will fire at, no signup, no scheduler to configure. It's a genuine cron job next execution time tool, walking forward minute by minute from the start point and checking each field, minute, hour, day of month, month, and day of week, against your expression to calculate cron schedule times until it collects as many matches as you've asked for.
6-Field Cron Syntax and Seconds Precision
Most cron guides only cover the standard 5-field format, but this is also a genuine cron 6 field parser and a quartz cron next run time calculator, supporting the seconds-prefixed syntax used by Quartz, Spring Scheduler, and several other job schedulers. Paste a 6-field cron expression with seconds and it's recognized automatically, no separate mode toggle required, making this a real cron expression with seconds calculator for anyone working outside plain Unix cron.
Calculating from a Custom Start Date
By default, run times are calculated from right now, but the optional start date field turns this into a genuine tool for a cron schedule from custom date, answer "what will run next after this deployment, incident, or maintenance window" instead of just "what runs next from this exact second". Enter any ISO date and time and every calculated run time picks up from there instead of the current moment.
Cron Field Syntax Reference
An asterisk (*) matches every value in that field. A comma-separated list like 1,15 matches only those specific values. A range like 1-5 matches every value in between, inclusive. A step like */15 or 10-20/5 matches every Nth value starting from the range's beginning. Named months (jan, feb) and days (mon, tue) work anywhere a number would, and critically, both 0 and 7 are treated as Sunday in the day-of-week field, matching the POSIX cron convention that trips up hand-written parsers which only check for 0.