Pregnancy Due Date Calculator
Estimate Your Due Date
The Due Date Calculator estimates the delivery date based on your last menstrual period (LMP), ultrasound, conception date, or IVF transfer date.
Understanding Due Dates
Last Menstrual Period Calculation
The most common method estimates your due date by adding 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day cycle with ovulation on day 14. If your cycles are longer or shorter, the calculation adjusts accordingly.
Conception Date Calculation
If you know your conception date, your due date is calculated by adding 266 days (38 weeks) to that date. This method is typically only accurate if you’ve tracked ovulation through methods like temperature charting or ovulation tests.
IVF Transfer Calculation
For IVF pregnancies, the due date is calculated from the embryo transfer date. For a 3-day embryo, add 263 days. For a 5-day embryo, add 261 days. Your fertility clinic will provide the most accurate due date based on your specific treatment.
Normal Variations
Only about 5% of women deliver on their exact due date. Most births occur within 2 weeks before or after. Babies born between 37-42 weeks are considered full term.
Related Tools: 1) Online Pregnancy Calculator – Know Your Baby’s Due Date Today, 2) Healthy Pregnancy Weight Gain Calculator & Guidelines, 3) Pregnancy Conception Calculator: Calculate Your Ovulation and Fertility Window
How to Use the Pregnancy Due Date Calculatore
Follow these simple steps to estimate your baby’s delivery date:
1. Choose Your Calculation Method
Select one of three tabs based on the information you have:
- Last Menstrual Period (LMP) (Most common method)
- Conception Date (If you tracked ovulation or know conception date)
- IVF Transfer (For IVF pregnancies)
2. Enter Your Details
For LMP Method:
- Select the first day of your last period using the calendar.
- Choose your average cycle length (default is 28 days).
For Conception Date Method:
- Enter the date you conceived (if known).
For IVF Method:
- Select the type of embryo transfer (3-day or 5-day).
- Enter the transfer date.
3. Click “Calculate Due Date”
The tool will instantly display:
✅ Estimated Due Date (40 weeks from LMP or adjusted for other methods).
✅ Current Gestational Age (How far along you are in weeks/days).
✅ Conception Date (Estimated or entered).
✅ Current Trimester (1st, 2nd, or 3rd).
4. Review the Results
- A visual timeline shows your pregnancy progress (trimesters and key milestones).
- Important Note: Only 5% of babies are born exactly on the due date—most arrive within 2 weeks before or after.
Tips for Accuracy
🔹 LMP Method: Best if you have regular periods.
🔹 Ultrasound Dating: More accurate if available (consult your doctor).
🔹 IVF Pregnancies: Use the transfer date for precise results.
Why Trust This Calculator?
- Based on medical guidelines (280 days from LMP or 266 days from conception).
- Accounts for cycle length variations.
- Always consult your healthcare provider for personalized care.
Example Calculation
If your last period started on June 1, 2024:
- Select LMP tab → Enter
June 1, 2024. - Keep cycle length at 28 days (default).
- Click “Calculate.”
- Result: Due date = March 8, 2025 (40 weeks later).
This tool is designed for quick estimates—your doctor will provide the most accurate dating scan. ❤️
Frequently Asked Questions (FAQ) – Pregnancy Due Date Calculator
1. How accurate is the due date calculator?
The calculator provides an estimate based on medical standards (280 days from LMP or 266 days from conception). Only 5% of babies are born on the exact due date—most arrive within 2 weeks before or after. For higher accuracy, consult an ultrasound scan.
2. Which calculation method is best?
- LMP Method: Use if you know the first day of your last period (works well for regular cycles).
- Conception Date: Use if you tracked ovulation (e.g., via tests or fertility apps).
- IVF Transfer: Most precise for IVF pregnancies (enter embryo transfer date).
3. My cycle isn’t 28 days. Does this affect the due date?
Yes! The calculator adjusts for cycle length. If your cycle is longer than 28 days, ovulation likely occurs later, so your due date may be slightly later.
4. Why is my ultrasound due date different from this calculator?
Ultrasounds measure fetal growth and can provide a more accurate estimate, especially in the first trimester. Always prioritize your doctor’s dating scan.
5. Can I use this calculator if I don’t remember my LMP?
Try the conception date method if you know when you ovulated. Otherwise, an ultrasound is the best alternative.
6. What does “gestational age” mean?
It’s how far along your pregnancy is, counted from the first day of your last period (not conception). For example, at 4 weeks pregnant, fertilization likely occurred ~2 weeks ago.
7. What if my due date has passed?
Only 5-10% of pregnancies go past 42 weeks. Contact your healthcare provider—they may recommend monitoring or induction.
8. Does IVF pregnancy calculation differ?
Yes! IVF due dates are based on the embryo transfer date:
- 3-day embryo: Due date = Transfer date + 263 days.
- 5-day embryo: Due date = Transfer date + 261 days.
9. Why does the calculator show a range of dates?
Pregnancy naturally varies. The tool highlights full-term (37–42 weeks) to remind users that delivery timing is flexible.
10. Is this tool a substitute for medical advice?
No. Always consult your doctor for personalized care, especially if you have irregular cycles, IVF, or high-risk factors.