When is your baby due?
Estimate your due date from your last period, conception, or IVF transfer — and see how far along you are today.
Pick a date to see your estimate.
This is a friendly estimate, not medical advice. A first-trimester ultrasound is the most accurate way to date a pregnancy — always go by what your doctor or midwife tells you.
About due dates
How is my due date calculated?
The classic method (Naegele’s rule) counts 280 days (40 weeks) from the first day of your last period. If you know your conception or ovulation date, we count 266 days from there instead. For IVF, we count from your embryo transfer. Only about 1 in 20 babies actually arrives on the due date — most come in the two weeks either side.
What if my cycle isn’t 28 days?
Cycle length shifts when you ovulate, so it shifts the estimate. Enter your average cycle length and we adjust the due date accordingly — a longer cycle pushes it a little later, a shorter one a little earlier.
Is this as accurate as an ultrasound?
No. A dating ultrasound in the first trimester is the most accurate way to set a due date, and your provider may adjust it. This calculator is a friendly estimate to give you a rough timeline, not a medical result.
When do the trimesters start and end?
Counting from your last period: the first trimester runs through week 13, the second from week 14 to 27, and the third from week 28 until birth.
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