Ovulation Calculator - Fertility Calendar

Ovulation calculator for family planning — free fertile window and conception calendar. INTRODUCTION Plan with confidence using Trencada's free ovulation calculator. Enter the first day of your last period and your average cycle length to get your estimated ovulation day, fertile window, next period and a due date if conception occurs — with a visual fertility calendar. Runs entirely in your browser — no signup needed. HOW TO USE 1. Enter the first day of your last period. 2. Enter your average cycle length (21–45 days; 28 is typical). 3. Click Calculate fertile window to see your estimated ovulation day, fertile window and a calendar view. 4. The most fertile days are the 2 days before ovulation plus ovulation day itself. KEY FEATURES - Estimated ovulation day and 7-day fertile window. - Visual fertility calendar with period, fertile and ovulation highlights. - Next period prediction and conception due date. - Custom cycle length (21–45 days) and luteal phase setting. - 100% client-side — nothing uploaded or stored. WHY CHOOSE TRENCADA No signup, no paywall, no app. The ovulation calculator works entirely in your browser and gives you the fertility calendar couples actually need — free and private forever. FAQ 1. Is the ovulation calculator really free? Yes — unlimited calculations, free forever, no account needed. 2. What are the most fertile days? The 2 days before ovulation plus ovulation day itself. 3. How accurate is the estimate? Based on averages — combine with ovulation tests or BBT tracking for accuracy. 4. Is my data uploaded anywhere? No — everything runs locally in your browser.