← All Tools

Pregnancy Due Date Calculator

Estimate your due date, see how far along you are, and track key pregnancy milestones week by week.

Pregnancy Details

Standard is 28 days. Adjusts due date for longer/shorter cycles.

👶

Enter your details and click Calculate Due Date to see your results.

How Due Dates Are Calculated

This calculator uses Naegele's rule, the standard method used by healthcare providers. From your last menstrual period (LMP), it adds 280 days (40 weeks) to estimate your due date. If your cycle is longer or shorter than 28 days, the calculation adjusts accordingly.

Naegele's rule formula: LMP + 280 days + (cycle length - 28 days) = Estimated Due Date

For conception date, 266 days (38 weeks) are added. For IVF transfers, the calculation accounts for embryo age at transfer (3 or 5 days).

Important Notes on Accuracy

Only about 5% of babies are born on their actual due date. Most births occur within a window of two weeks before or after the estimated date.

First-time mothers tend to deliver slightly later than the due date on average. A "full term" pregnancy is considered anywhere from 37 to 42 weeks.

Ultrasound dating, especially in the first trimester, is typically more accurate than LMP-based calculations. Your healthcare provider may adjust your due date after an early ultrasound.

This calculator is for informational purposes only and does not replace medical advice. Always consult your healthcare provider for personalized guidance.