Pregnancy Due Date Calculator
Estimate a due date using Naegele's rule (last menstrual period + 280 days), or work back from a known conception date. Also shows the trimester dates and how far along you are today.
Calculate from
First day of your last period
Only about 1 in 20 babies arrive on the estimated due date. A dating ultrasound in the first trimester is the most accurate method — always go by what your obstetrician says.
FAQ
- How accurate is the due date?
- It's an estimate — only about 5% of babies are born on the exact date. A first-trimester dating scan is more accurate than the last-period method, especially with irregular cycles.
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Free to use, no sign-up. Calculations run in your browser — nothing you type is sent to a server. These tools are for general information only, not professional advice. See the full tool list.