justyourcalculatorOvulation Calculator
Your ovulation day and fertile window for the next six cycles.
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Ovulation Calculator
Ovulation and fertile days for 6 cycles
Usually 21 to 35 days.
Days from ovulation to your period. 14 if unsure.
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How the ovulation calculator works
Ovulation happens a fixed time before your next period: the luteal phase, usually 12 to 14 days. So ovulation day = next period start - luteal phase. The fertile window runs from 5 days before ovulation to 1 day after, because sperm survive up to 5 days and the egg about a day.
The calendar repeats this for each of your next six cycles using your average cycle length. The due date shown is what you'd get if you conceived on that ovulation day (266 days later).
Using and checking your result
Published by JustYourCalculator. Check the units and assumptions above, and compare a known example before relying on the output. Calculations use browser arithmetic and may round displayed values.
This tool provides an estimate, not a diagnosis, treatment plan or individualized medical advice. Population formulas may not fit children, pregnancy, athletes or people with health conditions. Discuss health decisions with a qualified clinician.
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