pregnancy calculator by date of conception ivf
Free Pregnancy Calculator 2026 to calculate your due date, pregnancy week, conception date and full pregnancy timeline based on LMP or conception date.
Pregnancy Calculator
Find your estimated due date and pregnancy progress easily
How Does the Pregnancy Due Date Calculator Work?
This calculator estimates key pregnancy dates using standard obstetric methods. By entering your last menstrual period (LMP) or IVF transfer date, the calculator applies proven medical formulas to determine your due date and track your pregnancy progress. The results represent estimates based on typical pregnancy development—actual delivery dates vary significantly based on individual factors, fetal development, and healthcare provider assessments.
Pregnancy Term & Due Date
A full-term pregnancy lasts approximately 40 weeks (280 days) from the first day of your last menstrual period. Due dates represent estimates rather than exact delivery dates. Medical research shows that only about 5% of pregnancies result in delivery on the calculated due date. Early-term births occur before 37 weeks, while post-term pregnancies extend beyond 42 weeks. Your healthcare provider monitors your pregnancy throughout all three trimesters and may adjust your estimated due date based on ultrasound measurements and clinical assessment.
How Can My Estimated Due Date Be Calculated?
Different medical methods determine pregnancy due dates depending on how pregnancy occurred. Healthcare providers select the most accurate method based on your individual circumstances, whether dating by menstrual history, ovulation timing, or fertility treatments.
Last Menstrual Period (LMP)
The Last Menstrual Period method represents the most commonly used approach in clinical practice. This method calculates the due date by assuming pregnancy began with ovulation occurring approximately 14 days after the first day of your last period. The calculation works best when you have regular menstrual cycles. Healthcare providers use this method because it's straightforward, requires minimal information, and aligns with standard obstetric guidelines. The formula assumes 280 days from LMP, though individual cycle variations may adjust this timeline.
IVF Transfer Date Method
In vitro fertilization (IVF) dating uses the embryo transfer date to calculate the pregnancy due date. The calculation differs slightly depending on whether a 3-day or 5-day embryo transfer occurred. For 3-day transfers, 266 days are added to the transfer date, while 5-day (blastocyst) transfers add 261 days. IVF dating methods often provide greater precision than LMP-based calculations because the exact developmental stage of the transferred embryo is known. This approach eliminates uncertainty from irregular cycles or unknown ovulation timing, making it particularly valuable for patients with fertility histories.
Understanding Your Pregnancy
This pregnancy calculator estimates your due date based on the first day of your last menstrual period (LMP) or conception date. The calculation assumes a typical pregnancy duration of 280 days (40 weeks) from the LMP. Keep in mind that only about 5% of babies are born on their exact due date, so this is an estimate. Your healthcare provider may adjust your due date based on ultrasound measurements.
Your Privacy is Protected
Your health data (last period date, conception date) is processed locally in your browser and is never stored, transmitted, or shared with any server. All calculations happen instantly on your device for complete privacy.
Reviewed by: VIP Calculator Health & Pregnancy Research Team
This Pregnancy Calculator follows the Naegele's Rule and standard obstetric methods used worldwide by healthcare professionals. Calculations are based on a 280-day (40-week) gestational period from the first day of the last menstrual period (LMP), consistent with guidelines from the American College of Obstetricians and Gynecologists (ACOG).
Transparency Note:
Due dates are estimates. Only 5% of babies are born on their exact due date. Ultrasound dating (especially in the first trimester) is more accurate than LMP-based calculations. Always consult your healthcare provider for personalized prenatal care and accurate due date determination.
Last Reviewed: December 2025 | Updated for 2026 medical standards
Important: This calculator provides estimates for educational purposes only. Every pregnancy is unique. Always consult with your healthcare provider for personalized medical advice, accurate due date determination, and prenatal care guidance.
📖How to Use the Pregnancy Calculator
- Enter the first day of your last menstrual period (LMP)
- Alternatively, enter your conception date if known
- Or input your due date to calculate backwards
- Click Calculate to see your pregnancy timeline
- Review trimester milestones and important dates
✨Key Features of the Pregnancy Calculator
- Calculate due date from LMP or conception date
- Determine current week and trimester
- Track pregnancy milestones
- Countdown to due date
- Fetal development information by week
🎯Benefits of Using the Pregnancy Calculator
- Plan for prenatal appointments
- Track baby's development week by week
- Prepare for each trimester
- Know important screening dates
- Share accurate information with healthcare providers
Frequently Asked Questions (FAQ)
How accurate is the due date calculation?
Due dates are estimates based on a 40-week pregnancy. Only about 5% of babies are born on their exact due date, with most arriving within two weeks before or after.
What if I don't know my LMP?
You can use your conception date or an ultrasound-determined due date. Early ultrasounds are the most accurate way to date a pregnancy.
When do the trimesters start and end?
First trimester: weeks 1-12, Second trimester: weeks 13-26, Third trimester: weeks 27-40.
Can the due date change?
Your healthcare provider may adjust your due date based on ultrasound measurements, especially if done in the first trimester.