Period Calculator – Predict Next Period & Ovulation
Free period calculator to predict your next menstrual cycle, ovulation date, and fertile window using your last period and cycle length.
Next Period: —
Ovulation: —
Fertile Window: — – —
Period Calculator – Predict Next Period & Ovulation
This period calculator helps estimate your next menstrual cycle, ovulation date, and fertile window. Enter the first day of your last period and your average cycle length to get accurate predictions instantly.
How to Calculate Next Period Date
Your next period is estimated by adding your average menstrual cycle length to the first day of your last menstrual period (LMP).
Next Period = Last Period Date + Cycle Length
Ovulation & Fertile Window Prediction
Ovulation typically occurs about 14 days before your next expected period. The fertile window includes the 5 days before ovulation and the ovulation day itself.
FAQ
How does a period calculator work?
It predicts your next period and ovulation date using your last menstrual period date and average cycle length.
What is a normal menstrual cycle length?
A normal menstrual cycle typically ranges from 21 to 35 days in adults.
When does ovulation occur?
Ovulation usually occurs about 14 days before the next expected period.
What is the fertile window?
The fertile window includes the 5 days before ovulation and the ovulation day when pregnancy is most likely.