Ovulation Calculator 2026 🌙 Dark Mode Estimate your ovulation date, fertile window, and next period using your cycle history — with multi-month predictions, a visual cycle wheel, symptom and BBT tracking, cycle history logging, and more, all calculated privately in your browser. ⚠️ Important: This calculator provides estimates only based on average cycle data. It is NOT a reliable method of contraception and should not be used to prevent pregnancy. Actual ovulation timing varies due to stress, health conditions, and individual physiology. Consult a healthcare provider for fertility or contraception guidance. Cycle Details First Day of Last Period (LMP) Average Cycle Length (days) ⓘ Luteal Phase Length (days) ⓘ Period Duration (days) Mode Trying to Conceive Trying to Avoid Pregnancy My cycles are irregular (show a wider range instead of one exact date) Auto-calculate cycle length from my logged history below Calculate Your Prediction Estimated Ov...