Due Date Calculator

Use this calculator to find your due date. This is just an estimate – not a guarantee! Most women, but not all, will deliver their babies within a week before or after this date range.

Calculation Method

Cycle Length

28 days


Last Period

Most pregnancies last about 40 weeks (or 38 weeks from conception). So the best way to estimate your due date is to count 40 weeks or 280 days, from the first day of your last period. Another way is to take the first day of your last period, subtract three months and add 7 days.So if your last menstrual period begins on April 11, 2020, you'll subtract three months back to January 11, 2020, then add 7 days, and your due date will be January 18, 2021. This is how the doctor will estimate the due date for pregnant women. But remember: it is completely normal to give birth a week earlier or later than the expected date.

Conception Date

The calculation of gestational age by date of intercourse applies to couples who remember the exact date when intercourse happened, to women who have a regular menstrual cycle and the date of ovulation is determined. The reason for this is that after ovulation, the egg only has one day to live while sperm can live in the female body for up to 5 days. Sperm can only fertilize eggs during this time period.According to this calculation, the first day of gestational age will be counted by marking the day of sexual intercourse and then adding 36 weeks or 266 days (given there's ovulation).


Calculating the week of pregnancy and the due date at artificial insemination will be more accurate than with normal conception. This is because you already know the exact date of embryo implantation or ovulation.When you are part of the growing tribe of IVF moms, the expected delivery date is calculated by adding up to 38 weeks (ie 266 days) from the time the egg was fertilized. Another calculation is to add 38 weeks, but subtract the number of days since the embryo has been implanted. For example, for 3-day transfer, 3 days will be deducted and for 5-day transfer, 5 days will be subtracted.