Estimate your due date and see how far along you are
Only a small share of babies arrive on the exact due date. Your doctor or midwife will confirm your dates.
This free pregnancy due date calculator estimates when your baby is due. Enter the first day of your last period or your conception date, and you will see your estimated due date, how many weeks and days pregnant you are today and which trimester you are in.
It also lists key dates, such as when the second and third trimesters begin and when full term starts.
Example: if the last period began on October 1, 2026 and the cycle is 28 days, the due date is Thursday, July 8, 2027. The second trimester begins at 14 weeks (January 7, 2027), the third at 28 weeks (April 15, 2027) and full term at 39 weeks (July 1, 2027). A conception date of October 15, 2026 gives the same due date. With a 32-day cycle the due date moves to July 12, 2027.
The most common method adds 280 days (40 weeks) to the first day of your last menstrual period, which assumes a 28-day cycle. If your cycle is longer or shorter than 28 days, the calculator moves the date by the difference. From a conception date, it adds 266 days.
Most people do not know the exact day of conception, but they usually know when their last period started. Conception normally happens about two weeks after that date, so pregnancy is dated from the period, and the weeks you hear about are counted the same way by doctors.
It is an estimate. Only a small share of babies are born on the exact due date, and most arrive within a few weeks before or after it. An early ultrasound can also adjust the date, so your doctor or midwife has the final say.
The first trimester runs to the end of week 13, the second from week 14 to the end of week 27, and the third from week 28 until birth.
Full term is commonly defined as 39 weeks to 40 weeks and 6 days. Early term is 37 weeks to 38 weeks and 6 days. The key dates list shows when 39 weeks begins.
If your cycles are irregular, or you conceived with IVF or other fertility treatment, your care provider will use other information, such as an ultrasound or the embryo transfer date, to set your due date. Use this calculator only as a rough guide.
Disclaimer: This calculator is for general information only and is not medical advice. Always confirm your due date and care plan with a doctor or midwife.