Pregnancy Due Date Calculator
HealthEstimate your due date and see how far along you are — from your last period, conception date, or IVF transfer date.
Estimated due date
Gestational age counts from the first day of your last period — two weeks before conception. Your provider may adjust your due date at your first ultrasound.
Worked Example — LMP of January 1, 2026
Frequently Asked Questions
The due date formula is the same regardless of how many babies you're expecting. In practice, twin pregnancies often deliver before the estimated due date, so treat this as an even more approximate estimate for twins.
Common Mistakes to Avoid
- Only about 5% of babies are born on their exact due date. This is a helpful estimate based on averages, not a guarantee. An ultrasound in the first trimester is considered the most accurate way to date a pregnancy — always confirm your estimate with your doctor.
- This isn't medical advice — it's a scheduling estimate. Use this to get a general sense of timing and gestational age, not to make clinical decisions. Your doctor's dating (especially from an early ultrasound) takes precedence over this calculator's estimate.
References
- ACOG (American College of Obstetricians and Gynecologists) — trimester boundaries and standard 280-day (Naegele's rule) due date estimation
Last reviewed July 2026
Was this calculator helpful?
Can't find a calculator you need?
More health & family tools
Age Calculator
Calculate exact age in years, months, and days from a date of birth.
BMI Calculator
Calculate Body Mass Index and see your healthy weight range.
Calorie Calculator
Calculate your daily maintenance calories and calorie targets for weight loss or gain.
BMR Calculator
Calculate your Basal Metabolic Rate using the Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle formulas.