Health Calculator • Pregnancy Estimator
Due Date Calculator.
Estimate your pregnancy due date using last menstrual period, conception date, or IVF transfer date, with trimester and full-term milestones.
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How to Use
Choose Method
Select LMP, conception date, or IVF transfer date.
Enter Date
Add the relevant pregnancy date and cycle length if needed.
View Estimate
Check estimated due date and trimester milestones.
Due Date Formula
Common LMP Method
Estimated Due Date = First Day of Last Period + 280 Days
First day of last menstrual period
Estimated conception date plus about 266 days
Transfer-date based estimate confirmed by specialist
Complete Due Date Guide
A pregnancy due date calculator estimates the expected delivery date based on pregnancy dating information. The most common method uses the first day of the last menstrual period and adds about 280 days, which is equal to 40 weeks.
Important: This calculator is only an estimate. Ultrasound dating and your doctor’s advice are more important for medical decisions.
Pregnancy dating can be calculated in different ways. If the last menstrual period date is known and cycles are regular, the LMP method is often used. If the conception date is known, the calculator can estimate the due date by adding about 266 days. IVF pregnancies may use transfer-date based calculations.
The estimated due date is not a guaranteed delivery date. Many babies are born before or after the due date. The date is mainly useful for planning prenatal appointments, trimester tracking, health monitoring, and preparation.
Cycle length can affect estimates because ovulation does not happen on the same day for everyone. A 28-day cycle is commonly used, but longer or shorter cycles may shift the estimated date slightly. This calculator allows cycle-length adjustment for LMP-based estimates.
Trimester milestones are also useful. The first trimester is the early pregnancy phase, the second trimester is often a more stable middle phase, and the third trimester leads toward birth preparation. Always follow medical checkups and screening schedules recommended by your healthcare provider.
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Due Date FAQs
What is a due date calculator?
A due date calculator estimates the expected delivery date based on the last menstrual period, conception date, or IVF transfer date.
How is due date calculated from LMP?
The common method adds about 280 days, or 40 weeks, to the first day of the last menstrual period.
Is the due date exact?
No. The due date is an estimate. Actual delivery can happen before or after the estimated date.
Can I calculate due date from conception date?
Yes. If conception date is known, the calculator estimates due date by adding about 266 days.
Can IVF due date be calculated?
Yes. IVF due date can be estimated from the embryo transfer date, but your fertility specialist should confirm the date.
What is full-term pregnancy?
Full-term pregnancy generally begins around 37 weeks, but medical guidance should always come from your doctor.
Why does cycle length matter?
Cycle length can affect ovulation timing, so due date based on LMP may be adjusted when cycles are longer or shorter than 28 days.
When does the first trimester end?
The first trimester usually ends around 12 weeks of pregnancy.
When should I confirm pregnancy dates?
You should confirm pregnancy dating with a qualified doctor, especially through clinical evaluation and ultrasound guidance.
Is this calculator medical advice?
No. This calculator is for educational estimation only and does not replace medical consultation.