Pregnancy calculator

The calculator estimates your due date by counting 40 weeks from the first day of your last menstrual period. This method assumes a regular menstrual cycle and provides an estimate rather than an exact delivery date.

If your cycles are irregular, you are unsure of the date of your last period, or your pregnancy was conceived through assisted reproduction, your healthcare provider may use a different method to estimate your due date.

Your due date is a guide rather than a guarantee. It is normal for birth to happen earlier or later than the estimated date.

Your doctor may compare your estimated due date with ultrasound measurements, particularly during early pregnancy, and adjust it if necessary.

Your estimated due date helps your healthcare team plan your maternity care. It can be used to schedule screening tests and antenatal appointments, monitor your baby’s growth and development, and determine when further assessment may be needed.

It also gives you a useful timeframe for planning for your baby’s arrival.

A pregnancy calculator cannot predict exactly when labour will begin, guarantee your baby’s size or development, identify complications, or replace medical assessment.

Regular antenatal appointments remain important for monitoring your health and your baby’s development throughout pregnancy.

Speak to your doctor to confirm your pregnancy and estimated due date, particularly if your menstrual cycles are irregular, you are unsure when your last period began, you have pregnancy symptoms you are concerned about, or your pregnancy followed fertility treatment.

An early ultrasound can help establish a more accurate pregnancy timeline where needed.

If you conceive through assisted reproductive treatment, including IVF, your due date may be calculated differently because the date of conception or embryo transfer is known more precisely.

Your fertility or maternity team will calculate the most appropriate estimated due date and monitor your pregnancy accordingly.