Calculate your due date based on the first day of your last menstrual period, and see which pregnancy week and trimester you're in right now.
The calculator uses Naegele's rule, the most common method for estimating a due date, adjusted for cycle length:
Pregnancy is counted from the first day of your last menstrual period, even though conception itself typically happens around two weeks later. A full-term pregnancy lasts on average 40 weeks from this date. The first trimester runs through week 13, the second trimester through week 27, and the third trimester runs until birth.
The exact time of conception is rarely known with certainty, while the date of the last menstrual period is easier to pin down. That's why healthcare providers use this date as the standard starting point.
The calculator adjusts the due date based on the cycle length you enter. A longer cycle gives a later due date, a shorter cycle gives an earlier due date.
Yes. An ultrasound measurement early in pregnancy is considered more precise than calculating from the last menstrual period alone, and is therefore often used to adjust the due date by your midwife or doctor.