Pregnancy Due Date Calculator
Estimate your baby's delivery date from your last period, conception date, ultrasound, or IVF transfer — and follow your pregnancy week by week.
Please choose a valid past date.
Default is 28 days.
Estimated due date
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Only ~4% of babies arrive on the exact due date — most come within a week either side.
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About due date calculation
How it works
The most common method (Naegele's rule) adds 280 days — 40 weeks — to the first day of your last period, adjusted for your cycle length. Conception dating adds 266 days from conception. IVF adds 261 days for a Day 5 blastocyst or 263 days for a Day 3 embryo.
Ultrasound dating uses the gestational age measured on an early scan, which is often the most accurate method.
Good to know
- Early term is 37–38 weeks, full term 39–40, late term 41, post-term 42+.
- Twins and multiples usually arrive earlier.
- Your provider may adjust the date after an ultrasound.
- Regular prenatal care is essential throughout pregnancy.
This tool provides estimates for informational purposes only and is not a substitute for professional medical advice. Always consult your doctor or midwife.