Ovulation Calculator

Ovulation Calculator

First day of last period

Average cycle length (days)

Typically 21-35 days.

Period length (days)

Usually 3-7 days.

Luteal phase length (days)

Typically 12-16 days.

Results

Ovulation Date:

Fertile Window:

Next Period:

How it works

Ovulation occurs approximately 14 days before your next period. The fertile window includes the 5 days before ovulation and the day of ovulation itself. Calculations assume a consistent cycle length.