Fertility Tools · Ovulation Calculator

Ovulation Calculator
for Nigerian Women

Calculate your fertile window and most likely ovulation date. Enter your last period date and cycle length for an instant estimate — and understand how to maximise your chances of conception.

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Free calculatorFertile window estimatedConception tipsAkoka, Lagos

Calculator

Ovulation & Fertile Window Calculator

Enter the first day of your last period and your average cycle length to estimate your next ovulation date and fertile window.

FIRST DAY OF LAST PERIOD

AVERAGE CYCLE LENGTH (days)

Important limitation: This calculator assumes regular cycles and typical ovulation on day 14 of a 28-day cycle. Women with irregular cycles (PCOS, thyroid disease) may not ovulate predictably. A follicular tracking scan at Mascot Healthcare is the only way to confirm that ovulation has actually occurred.

Understanding Ovulation and Fertility

In a typical 28-day cycle, ovulation occurs on approximately day 14. The egg survives for only 12–24 hours after release. However, sperm can survive in the female reproductive tract for up to 5 days — making the 5 days before ovulation, plus the day of ovulation, the fertile window.

Signs of ovulation

Cervical mucus change: Becomes clear, slippery, and stretchy ('egg white' consistency) — the most reliable natural sign
Mild pelvic pain (Mittelschmerz): A brief one-sided twinge — felt by about 20% of women
Basal body temperature (BBT) rise: A subtle rise of 0.2–0.5°C after ovulation — confirms ovulation has occurred but is too late to act on
LH surge: Detected by ovulation predictor kits (OPKs) in urine — reliably predicts ovulation 24–36 hours before it occurs

When the calculator is not reliable

This calculator assumes regular cycles. Women with PCOS, thyroid disease, significant stress, extreme exercise, or recent hormonal contraceptive use may have irregular or absent ovulation that this calculator cannot predict. For these women, follicular tracking ultrasound scans at Mascot Healthcare — monitoring follicle development with serial scans across the cycle — are the only reliable way to identify the fertile window.

Questions

FAQs

How can I confirm I am actually ovulating?

A blood progesterone test on day 21 of a 28-day cycle (7 days after expected ovulation) confirms whether ovulation occurred. A progesterone above 16–30 nmol/L (depending on the assay) indicates ovulation. Follicular tracking scans directly visualise follicle growth and collapse (confirming ovulation). Both available at Mascot Healthcare.

I have irregular periods. Is this calculator useful for me?

Not reliably. Irregular cycles — common in PCOS — mean ovulation cannot be predicted from last period date alone. Follicular tracking scans every 2–3 days during the cycle are the most accurate approach.

Book Follicular Tracking for Precise Ovulation Detection

Serial ultrasound scans at Mascot Healthcare, Akoka confirm exactly when you ovulate. From ₦7,000/scan.

💬 Book via WhatsApp 📞 0816 586 6252

Follicular scan

₦7,000 per scan

Progesterone test

Day 21

Walk-in

Mon–Sat

Ovulation Calculatorfor Nigerian Women