Ovulation Calculator
Use the Ovulation Calculator for a fast estimate with clear inputs, formula guidance and related tools.
Formula / method
Estimated ovulation ≈ next period − 14 days.
Cycles vary; this is not contraception or medical advice.
How to use
Enter measurements using the units shown and use recent, representative values.
What this calculator answers
The Ovulation Calculator uses First day of last period, Average cycle length (days) to calculate the requested result. The core method is Estimated ovulation ≈ next period − 14 days.. This makes the assumptions visible so you can check whether the inputs match your situation.
How to get a useful result
Enter measurements using the units shown and use recent, representative values.
How to interpret it
Health and fitness formulas are screening or planning estimates, not a diagnosis or individualized medical recommendation.
Before relying on the number
Recheck unusual inputs, confirm units and compare the result with any official quote, statement, specification or rule that applies to the real decision. Small changes in rates, time periods or measurements can materially change some results.