Due Date Calculator
A due date calculator helps expectant parents calculate their baby's estimated due date and track important pregnancy milestones. Use our free due date calculator to determine your baby's arrival date based on your last menstrual period (LMP) or conception date. This tool provides accurate pregnancy calculations including conception date, current pregnancy week, trimester information, and key developmental milestones. Calculate your due date instantly to plan for maternity leave, baby preparations, and prenatal care appointments throughout your pregnancy journey.
Free • Accurate • Pregnancy planning • Milestones
How Due Date Calculation Works
Due Date Calculation Formula
Due Date = LMP + 280 days (40 weeks)
Naegele's Rule: LMP + 7 days - 3 months
Conception Method: Conception Date + 266 days
Ultrasound Method: Crown-rump length measurement
Accuracy Range: ± 2 weeks for natural conception
Example Due Date Calculation
With a last menstrual period of March 1, 2024, the estimated due date is December 6, 2024. The conception date is approximately March 15, 2024. The first trimester ends around May 27, 2024, second trimester ends around September 9, 2024, and the third trimester begins.
This timeline helps parents prepare for their baby's arrival.
Benefits of Due Date Calculator
Frequently Asked Questions
How accurate are due date calculations?
Due dates are estimates with ± 2 weeks accuracy. Only 5% of babies are born on their exact due date. Most arrive between 37-42 weeks.
What if I don't know my LMP date?
If you don't know your LMP, your doctor can estimate due date through ultrasound measurements, typically done between 8-14 weeks.
Can due dates change during pregnancy?
Yes, due dates can be adjusted based on ultrasound measurements, especially if there's a significant difference from LMP calculations.
Related Pregnancy Calculators
Calculate Your Baby's Due Date
Get accurate due date calculations and plan for your baby's arrival with confidence.
Use Due Date Calculator