Pregnancy Calculator
📖 Understanding Your Pregnancy Due Date
Our pregnancy calculator uses the first day of your last menstrual period (LMP) and your average cycle length to estimate your baby’s arrival. This method, known as Naegele’s rule, is the same one used by many healthcare providers.
Frequently Asked Questions
🔹 What is a pregnancy due date?
The due date (estimated date of delivery) is the day your baby is expected to be born. It is calculated as 40 weeks (280 days) from the first day of your last period. Only about 5% of babies arrive exactly on their due date — most are born within two weeks before or after.
🔹 How is the due date calculated?
The calculator adds 280 days to your LMP, then adjusts for your cycle length. For a 28‑day cycle, ovulation occurs around day 14. If your cycle is longer (e.g., 35 days), ovulation is later, so the due date is pushed forward. If it’s shorter (e.g., 21 days), the due date is moved earlier.
🔹 How accurate is this pregnancy calculator?
It gives a good estimate based on the standard formula. However, variations in ovulation, irregular cycles, and other factors can affect the actual due date. An ultrasound performed in the first trimester is often more precise.
🔹 Can I calculate my due date from the conception date?
Yes — if you know the exact date of conception, simply add 266 days. Our tool also shows the estimated conception date based on your LMP and cycle length, which you can use as a reference.
🔹 What are the pregnancy trimesters?
First trimester: weeks 1–13
Second trimester: weeks 14–26
Third trimester: weeks 27–40 (until birth)
