Pregnancy Due Date Calculator
Free online Pregnancy Due Date Calculator.
Calculator
How to Use
- Enter the required values
- Click Calculate to see the result
- Review the detailed output
Formula
Due Date = LMP + 280 days (40 weeks). Alternative: Conception date + 266 days. Naegele's rule: LMP + 7 days - 3 months + 1 year.
Example Calculations
Standard Calculation
Input: LMP: January 1, 2026
Result: Due date: October 8, 2026
Current Week
Input: LMP: March 15, 2026, Today: October 26, 2026
Result: 32 weeks, 3 days pregnant (Third trimester)
From Conception
Input: Conception date: June 1, 2026
Result: Due date: February 22, 2027
About This Calculator
Free online pregnancy due date calculator. Calculate instantly in your browser with our easy-to-use tool. No sign-up required.
Our pregnancy due date calculator is free, easy to use, and provides instant results. All calculations are performed in your browser for privacy and speed.
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Frequently Asked Questions
How is due date calculated?
Add 280 days (40 weeks) to first day of last menstrual period. Ultrasound can be more accurate.
Due date accuracy?
Only 4-5% arrive on exact due date. Most within two weeks before or after.
Trimesters of pregnancy?
First (weeks 1-12), second (13-27), third (28-40). Each has different milestones.
When to start prenatal care?
As soon as pregnancy is suspected, ideally within 8 weeks. Includes confirming pregnancy and identifying risks.
How many weeks pregnant?
Count weeks from first day of last menstrual period to today. This is the standard medical method.