Pregnancy Due‑Date & Week Calculator

Enter the first day of your last menstrual period (LMP) to estimate your due date and see which week you are currently in. This tool uses the average length of human pregnancy (40 weeks) to provide an approximate due date.

How we estimate your due date

Pregnancy is typically measured from the first day of your last menstrual period because it is difficult to pinpoint the exact date of conception. A full‑term pregnancy lasts around 40 weeks (280 days). Our calculator adds 280 days to your LMP to estimate when your baby might arrive.

Keep in mind:

• Due dates are only an estimate; only about 5% of babies arrive on their predicted due date.
• Ultrasound scans can provide a more accurate estimate of gestational age.
• Always consult your midwife or doctor for personalised care and advice.