Example: First day of last period: 2026-07-01 → Estimated due date: Wed, Apr 7, 2027.
Currently: 4 weeks along (from LMP)
End of first trimester: Wed, Sep 30, 2026
Method: Naegele’s rule (LMP + 280 days)
Frequently asked questions
How do I calculate pregnancy due date? Enter your numbers above and the result updates instantly. For example: First day of last period: 2026-07-01 → Estimated due date: Wed, Apr 7, 2027.
Is this Pregnancy Due Date Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for pregnancy due date. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.