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.
Medical disclaimer: This calculator is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Results are general estimates and may not reflect your individual circumstances. Always consult a qualified healthcare professional before making decisions about your health.
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 Add 280 days Due date: Oct 7, 2024 If today is April 1: 91 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.
What happens at 40 weeks?
You reach your due date! If labor hasn't started, you are monitored. Induction is usually discussed by 41-42 weeks.
Does IVF change the due date calculation?
Yes, IVF dates are precise because the exact fertilization/transfer time is known. We add 266 days to the fertilization date (minus embryo age).