Menstrual Cycle Calculator
Predict your next period, ovulation date, and fertile window.
July 2026
Current Cycle
Next Period
July 10, 2026
Ovulation Day
July 24, 2026
Fertile Window
Jul 19 – Jul 25
Next 3 Cycles
Aug 7 – Aug 11
Aug 21
Aug 16 – Aug 22
Sep 4 – Sep 8
Sep 18
Sep 13 – Sep 19
Oct 2 – Oct 6
Oct 16
Oct 11 – Oct 17
This is an estimate based on average cycle patterns. Cycles vary and this tool is not a substitute for medical advice.
About Menstrual Cycle Calculator
This free menstrual cycle calculator helps you predict your next period, ovulation date, and fertile window from your last period date and average cycle length. Cycle lengths typically range from 21 to 35 days, with ovulation occurring approximately 14 days before the next period. The fertile window spans roughly five days before ovulation through one day after. Use this tool to plan ahead and better understand your body's natural rhythms — all calculations happen entirely in your browser and nothing is sent to any server.
Private & free — this tool runs entirely in your browser.