Baby Due Date
Calculate Baby Due Date by entering start and end dates or times. Get precise durations in years, months, days, hours, and minutes.
Formula
Due Date = LMP + 280 days (or Conception + 266 days)
This Due Date Calculator computes results from your provided inputs using the calculator's underlying model.
Worked Examples
Example 1: LMP Calculation
Problem:Last period started January 1, 2024.
Solution:LMP: Jan 1\nAdd 280 days\nDue date: Oct 7, 2024\n\nIf today is April 1:\n91 days = 13 weeks pregnant
Result:Due October 7 (13 weeks along)
Frequently Asked Questions
How is due date calculated?
From LMP: add 280 days (40 weeks). From conception: add 266 days (38 weeks). Only 5% of babies arrive on their due date. Normal range: 37-42 weeks.
When is the baby viable?
24 weeks is generally considered viability threshold. Survival rates: 24 wks ~50%, 28 wks ~90%, 32 wks ~95%. Full term is 39-40 weeks.
How often do due dates change?
Due dates may be adjusted if an early ultrasound shows a size difference of >7 days from the LMP-based date.
Can I calculate due date if I have irregular periods?
LMP is less accurate for irregular cycles. An early ultrasound or known conception date is better. If using LMP, calculations assume a 28-day cycle.