How to Calculate Ovulation
What is Ovulation?
The ovulation calculator predicts when ovulation is most likely to occur and identifies the fertile window — the days when conception is possible. Ovulation typically occurs 14 days before the next expected period. The fertile window spans 5 days before ovulation, the day of ovulation, and 1 day after, as sperm can survive up to 5 days in the reproductive tract.
Formula
- LMP
- LMP value — Variable used in the calculation
Step-by-Step Guide
- 1Ovulation day estimate = LMP + (cycle length − 14 days)
- 2Fertile window = 5 days before ovulation to 1 day after
- 3Egg is viable for 12–24 hours after ovulation
- 4Sperm can survive 3–5 days in the reproductive tract
Worked Examples
Frequently Asked Questions
What is Ovulation Calc?
The ovulation calculator predicts when ovulation is most likely to occur and identifies the fertile window — the days when conception is possible. Ovulation typically occurs 14 days before the next expected period
How accurate is the Ovulation Calc calculator?
The calculator uses the standard published formula for ovulation calc. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Ovulation Calc calculator use?
This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Ovulation Calc calculator use?
The core formula is: Ovulation day estimate = LMP + (cycle length − 14 days). Each step in the calculation is shown so you can verify the result manually.
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