Calculate your estimated due date based on the first day of your last menstrual period (LMP). Standard pregnancy is about 280 days (40 weeks) from the first day of your last period.
Enter Your Measurements
Enter how many days ago your last period started (0 for today)
Results
Days Until Due Date
280
days
Weeks Pregnant (Today)
0
weeks
Formula
How to Use This Calculator
How to Use
- 1
Enter the first day of your last menstrual period.
- 2
The calculator shows your current weeks of pregnancy and estimated due date.
- 3
Note: Due dates are estimates. Most babies arrive within 2 weeks of the due date.
Frequently Asked Questions
Frequently Asked Questions
How accurate is the due date calculator?
What if I don't remember the exact date of my last period?
What is the difference between due date and conception date?
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About This Calculator
This calculator uses the formula: Due Date = First Day of Last Period + 280 days (40 weeks). All calculations follow industry-standard methods. Results are estimates — always verify with a licensed professional for structural or code-compliant work.
Built and maintained by the CalcSmart team. Last updated March 2026.
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<iframe src="https://calcsmart.io/embed/pregnancy-due-date-calculator" width="100%" height="520" frameborder="0" style="border-radius:8px;border:1px solid #e5e7eb" title="Pregnancy Due Date Calculator"></iframe>Free to embed. Attribution link included automatically.