Calculator

Ovulation Calculator

Calculate your estimated ovulation date, fertile window, and next expected period from your cycle details.

Calculate Fertile Window

Enter the first day of your last period and your usual cycle length. The estimate assumes ovulation happens around 14 days before the next period.

Ovulation Day

Fertile Window

Next Period

The fertile window is usually the 5 days before ovulation plus ovulation day.
Cycles can vary, so use this as a planning guide rather than a medical diagnosis.
If periods are irregular, very painful, absent, or unusually heavy, speak with a gynecologist.