Pregnancy Due Date Calculator
Estimate your due date and how many weeks pregnant you are, from the first day of your last period.
The first day your last menstrual period started.
Usually 28 days — adjust if yours differs.
Choose the first day of your last period to see your due date.
An estimate based on Naegele's rule (a 280-day pregnancy). Only an ultrasound and your doctor can confirm your due date.
About this tool
Whether you have just found out you are expecting or you are planning ahead, two of the first questions on every parent's mind are how many weeks pregnant am I and when is my due date. This pregnancy due date calculator gives you the answers instantly from the first day of your last period.
It could not be easier to use. Pick the first day of your last menstrual period on the calendar, and if your cycle runs longer or shorter than 28 days, adjust the cycle length for a closer result. The tool then works out:
- Your estimated due date
- How many weeks and days pregnant you are right now
- Which trimester you are currently in
Knowing these numbers helps you plan ahead with confidence, from booking prenatal appointments to arranging time off work and getting the nursery ready. Many parents-to-be also use it as a starting point to read up on caring for themselves and thinking about medical cover during pregnancy.
This tool is free with no sign-up and fully private, since everything is calculated right in your browser and nothing is sent anywhere. That said, do remember that the due date is only an estimate, only a small share of babies arrive exactly on the day, and the result is not a medical diagnosis. Regular prenatal visits and ultrasounds with your doctor remain the most accurate and safest way to follow your pregnancy and your baby.
How to use
- 1Select the first day of your last menstrual period on the calendar
- 2If your cycle is not 28 days, adjust the cycle length for a closer estimate
- 3Tap calculate to see your estimated due date
- 4See how many weeks pregnant you are now and which trimester you are in
Frequently asked questions
- How does this tool work out the due date?
- It counts 280 days, or about 40 weeks, from the first day of your last period. This is the standard method doctors use to estimate a due date.
- What if I cannot remember the first day of my last period?
- If you are unsure, the estimate may be off. The best step is to see a doctor for an ultrasound, which can date the pregnancy and due date far more accurately.
- Will my baby arrive exactly on the due date?
- Usually not. Only a small share of babies arrive on the predicted day. A pregnancy is generally considered full term anywhere from 37 to 42 weeks, so the due date is just an estimate.
- Is this tool free and private?
- Yes, it is free with no sign-up. Everything is calculated in your browser, and your period dates are never sent or stored anywhere.
- Can the result replace seeing a doctor?
- No. The result is an estimate to help you plan ahead, not a medical diagnosis. Regular prenatal check-ups with your doctor are always essential.