Estimate your ovulation day and fertile window based on your last period and cycle length.
| Estimated Ovulation Day | |
| Fertile Window Starts | |
| Fertile Window Ends | |
| Next Expected Period |
These are estimates based on average cycle patterns. Actual ovulation timing can vary - consider tracking basal body temperature or using ovulation predictor kits for more precision.
Based on the first day of your last period and your average cycle length, this calculator estimates your ovulation date and fertile window — the days each cycle when conception is most likely. Cycle length varies person to person, so entering your actual average (not just assuming 28 days) gives a more accurate estimate.
Ovulation typically occurs about 14 days before your next period begins. This calculator uses your last period start date and average cycle length to estimate your ovulation day, fertile window, and next expected period.
Pair this with our Pregnancy Calculator and Due Date Calculator for further family planning tools.
Ovulation typically occurs about 14 days before your next period begins.
It uses your last period start date and average cycle length to estimate your ovulation day, fertile window, and next expected period.
It gives your estimated ovulation day, fertile window, and next expected period.
Yes, it can be paired with a Pregnancy Calculator and Due Date Calculator for further family planning.
Your fertile window is estimated based on your last period start date and average cycle length, centered around your estimated ovulation day.