How is a Due Date Calculated?
A standard pregnancy lasts approximately 280 days (40 weeks) from the first day of your last menstrual period (LMP). This calculator uses Naegele's Rule, adjusting for your specific cycle length.
Pregnancy Due Date
Expected delivery date. Fast, accurate, and completely free.
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Estimated Due Date (EDD)
October 8, 2026
~280 Days Remaining
Pregnancy Timeline
Gestational Age
0 Weeks, 0 Days
Current Trimester
First Trimester
Baby Size Comparison
Size of a Poppy Seed
Mathematical Formula
\text{Estimated Due Date (EDD)} = \text{LMP Date} + 280 \text{ days} + (\text{Cycle Length} - 28 \text{ days})
LMP Date: First day of your last menstrual period.
280 days: Standard human gestation period (40 weeks).
Cycle Length - 28: Adjusts for cycles longer or shorter than the standard 28 days.
How to Use this Calculator
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Select the first day of your last menstrual period (LMP) from the date picker.
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Enter your average menstrual cycle length in days (default is 28).
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View your estimated due date, gestational progress, trimester, and baby development milestones.
Frequently Asked Questions (FAQ)
Are babies actually born on their due date?
Only about 4% to 5% of babies are born exactly on their estimated due date. Most are born within a two-week window before or after.
What are the trimesters of pregnancy?
Trimester 1: Weeks 1-13. Trimester 2: Weeks 14-27. Trimester 3: Weeks 28-40+.
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