Pregnancy
Fertile window
Sperm can survive several days, so the days before ovulation count too.
The Formula
From O - 5 to O + 1
Sperm can survive several days, so the days before ovulation count too.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| O | Ovulation day | days | The estimated day of release. |
What Each Symbol Means
Odays
Ovulation day
The estimated day of release.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate ovulation page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Ovulation, filed under Health. Every number the guide produces comes from substituting into this one line.