Pregnancy Due Date Calculator
Calculate your estimated due date based on your last period
Knowing your estimated due date (EDD) is one of the first exciting steps in pregnancy. This calculator uses your Last Menstrual Period (LMP) to project when your baby will arrive.
Calculator Inputs
Usually 28 days
Results
Enter values above to see your results
How It Works
We use Naegele's Rule, which adds 280 days (40 weeks) to the first day of your last period. We also adjust for cycle length if it differs from the standard 28 days.
Tips & Best Practices
- •Only about 4% of babies are born on their exact due date.
- •Most babies arrive within two weeks before or after the due date.
- •An early ultrasound is the most accurate way to date a pregnancy.
Frequently Asked Questions
How is due date calculated?
Pregnancy is calculated as 280 days from the first day of your last menstrual period, assuming a 28-day cycle. Conception usually happens about 2 weeks after your period starts.
What if my cycle is not 28 days?
If your cycle is longer, your due date will likely be later. If shorter, it will be earlier. Our calculator adjusts for this automatically.
Guides & Articles
The Data-Driven Pregnancy: Understanding Due Dates and Fertility Windows
Conception and pregnancy are biological processes governed by timing. We explain the math of ovulation windows and the Naegele's Rule for due dates.
Beyond BMI: The Truth About Body Composition in 2026
BMI is a useful screening tool, but it's not a diagnosis. We explore Body Fat %, TDEE, and the metrics that actually define metabolic health.
The Science of Energy Balance: TDEE, BMR, and Metabolism
Why do diets fail? Because they ignore the baseline data. Learn how to calculate your energy needs and manipulate them for weight loss or muscle gain.
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