The pregnancy calculator gives you an approximate due date, which it works out your due date by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28 day cycle, it is adjusted for longer or shorter cycles). Your period and ovulation are counted as the first two weeks of pregnancy.

Can you calculate due date by ovulation date?

Once you have a general idea of when you ovulated, you can use an adjusted LMP to find your due date with a pregnancy wheel. For example, if your menstrual cycle is usually 35 days long and the first day of your LMP was November 1: Add 21 days (November 22). Subtract 14 days to find your adjusted LMP date (November 8).

What day did I ovulate based on due date?

On average, a woman with a regular 28-day cycle ovulates on about the 14th day of each cycle. If a womans cycle is longer or shorter than 28 days, the predicted ovulation date is changed accordingly. For example, during a 24-day cycle (4 days shorter than the average), ovulation takes place on about the 10th day.

Does your cycle length affect your due date?

If your cycle lasts longer, the estimated due date will be later. If you have a shorter cycle, your due date will be earlier.