Wondering when your baby might arrive? Our free Pregnancy Due Date Calculator helps you estimate your expected due date based on the first day of your last menstrual period.
In just a few seconds, you can calculate your estimated due date, current pregnancy week, trimester, estimated conception date, and the number of days remaining until delivery.
Whether you’ve recently discovered you’re pregnant or simply want to track your pregnancy journey, this calculator provides a quick and easy estimate based on standard obstetric calculations.
How Does the Pregnancy Due Date Calculator Work?
Most healthcare professionals calculate pregnancy length from the first day of your last menstrual period rather than the date of conception.
Our calculator uses Naegele’s Rule, one of the most commonly used methods for estimating a due date:
- First day of your last menstrual period
- Plus 280 days (40 weeks)
- Equals your estimated due date
This method assumes a typical 28-day menstrual cycle with ovulation occurring around day 14.
Pregnancy Due Date Calculator
Calculate your estimated due date, current pregnancy week, trimester, and estimated conception date based on the first day of your last menstrual period.
What Information Will You Receive?
After entering your last menstrual period date, the calculator will provide:
Estimated Date of birth
The date your baby is expected to arrive based on a standard 40-week pregnancy.
Current Pregnancy Week
Your estimated gestational age expressed in weeks and days.
Current Trimester
An indication of whether you are in the first, second, or third trimester.
Estimated Conception Date
An approximate date when conception may have occurred.
Days Until Due Date
The estimated number of days remaining until your expected delivery.
How Accurate Is a Due Date Calculator?
A due date calculator provides an estimate rather than an exact prediction.
Only a small percentage of babies are born on their exact due date. Most healthy pregnancies result in delivery within a few weeks before or after the estimated due date.
Factors that may affect the accuracy of the calculation include:
- Irregular menstrual cycles
- Uncertain last menstrual period date
- Early or late ovulation
- Multiple pregnancies (twins or more)
- Medical conditions affecting pregnancy
Healthcare providers often use ultrasound measurements during the first trimester to confirm or adjust the estimated due date.
Understanding Pregnancy Trimesters
First Trimester (Weeks 1–13)
The first trimester is a period of rapid development for your baby. Many women experience symptoms such as fatigue, nausea, and breast tenderness during this stage.
Second Trimester (Weeks 14–27)
Often considered the most comfortable stage of pregnancy, the second trimester is when many women experience increased energy levels and begin to feel fetal movement.
Third Trimester (Weeks 28–40)
During the final trimester, your baby continues to grow and prepare for birth while your body gets ready for labor and delivery.
Frequently Asked Questions
How many weeks is a full-term pregnancy?
A full-term pregnancy typically lasts around 40 weeks from the first day of the last menstrual period.
Can my due date change?
Yes. Your healthcare provider may adjust your due date based on ultrasound findings, especially during early pregnancy.
What if I don’t know the exact date of my last period?
The calculator works best when you know the first day of your last menstrual period. If you’re unsure, consult your healthcare provider for a more accurate assessment.
How is pregnancy week calculated?
Pregnancy weeks are counted from the first day of your last menstrual period, not from the date of conception.
Do all babies arrive on their due date?
No. Only a small percentage of babies are born on their exact due date. Most arrive within a range of about two weeks before or after the estimated date.
Disclaimer
This calculator is intended for informational purposes only and should not replace professional medical advice. Always consult your doctor, midwife, or healthcare provider regarding your pregnancy, due date, and prenatal care.
