Conception Date Calculator – Estimate Your Ovulation, Conception, and Due Date
Are you wondering “When did I conceive?” or trying to calculate your baby’s estimated due date? Our free Conception Date Calculator is designed to give you fast, medically accurate answers using the date of your last menstrual period (LMP) and your average menstrual cycle length. Whether you’re trying to conceive, currently pregnant, or just curious about your fertility timeline, this powerful tool helps you track your ovulation window, estimate your conception date, and find your expected due date (EDD) — all in seconds.
What is a Conception Date Calculator?
A conception calculator helps estimate the date you likely conceived based on the first day of your last menstrual period (LMP) and your average cycle length. It also estimates your ovulation date, estimated due date (EDD), and how many weeks pregnant you are.
How to Use This Calculator
Enter the date of your last period (LMP)
Input your average menstrual cycle length (default is 28 days)
Click “Calculate” to instantly see your fertility timeline
What You’ll Learn
- Ovulation Date: The day you most likely ovulated
- Estimated Conception Date: When fertilization may have occurred
- Estimated Due Date (EDD): When your baby is expected to arrive
- Weeks Pregnant: How far along you are today
- also Check our other tool
Pregnancy Due Date Calculator – Find Your Baby’s Estimated Arrival Date
Why Use Our Conception Calculator?
- 100% free and easy to use
- Based on standard OB/GYN calculations
- No login or signup required
- Works on all devices – mobile, tablet, or desktop
- Instant results with helpful explanations
Who Can Use This Tool?
- Women trying to conceive (TTC)
- Pregnant women tracking their pregnancy week
- Health professionals looking for quick estimates
- Anyone curious about reproductive timing
Who Can Use This Tool?
Frequently Asked Questions (FAQs)
Q: When did I conceive if I know my due date?
A: Simply subtract 266 days (38 weeks) from your due date to get an estimate of your conception date.Q: Can I calculate my due date based on conception?
A: Yes, but conception is harder to pinpoint than LMP. If you know your ovulation date, you can add 266 days to estimate your due date.Q: What if I have irregular periods?
A: If your cycle is irregular, the calculator is less precise. You may get more accurate results using your ovulation date or with an early ultrasound.Q: How do I know how many weeks pregnant I am?
A: Our calculator estimates this based on your LMP. It’s the most common method used during early prenatal appointments.
How Accurate Is a Conception Calculator?
While only ultrasounds and medical exams can provide exact dates, our calculator uses the most common medical standard — a 280-day pregnancy length from the first day of your last period. This is the same method used by doctors to calculate your due date and conception window.
Please note that:
Ovulation can vary between women and cycles
Actual conception usually occurs 12–24 hours after ovulation
If you know your exact ovulation date, the estimate can be more precise
Still, for most women, this tool gives a very close estimate of key pregnancy dates.
Important Note
This calculator provides estimates for informational purposes only and is not a substitute for medical advice, diagnosis, or treatment. For personalized guidance, please consult your doctor or healthcare provider.