Pregnancy

Ovulation Predictor Calculator

Built by Kevin Glover · @gloverbuilds · Verified formula

Predict ovulation day and fertile window from cycle length. Free ovulation predictor.

📅 Updated April 2026 ✅ Formula verified 📖 4 min read 🆓 Free · No sign-up

In this article

How to Use This Calculator
Getting Accurate Results

Methods

Calendar: ovulation ~14 days before next period। OPK strips: ₹200-500/5 strips (dm, Amazon)। BBT: confirms after ovulation। Apps: Flo, Clue (Hindi support)। Fertile window: 5 days before to 1 day after ovulation।

India

Fertility awareness growing। Govt hospitals: free fertility counseling। OPK strips: available at Apollo Pharmacy, Netmeds, PharmEasy।

⚡ CalcWolf Insight

The most common fertility timing mistake: waiting for a positive OPK to have intercourse. By then, the best 2-3 days are already ending. Start every-other-day intercourse 5 days before expected ovulation. Treat the OPK as confirmation, not a starting signal.

Frequently asked questions

Most fertile?▾

1-2 days before ovulation।

OPK strips?▾

₹200-500 for 5 strips। Amazon, PharmEasy, Apollo Pharmacy।

✓ Math logic verified against primary sources → See our verification process

Kevin Glover · @gloverbuilds

Founder, CalcWolf · GLVTS · Blickr

All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →