How many weeks pregnant am I?

Counting from the first day of your last period, a full-term pregnancy is about 40 weeks. This tool works out your current week from your due date, which is 40 weeks from that start.

Why does the count use my due date?

Your due date is anchored to the start of pregnancy, so counting back from it gives a consistent current week. If your due date changed after a scan, use the updated date.

When will twins arrive?

Twins share the same estimated due date but very often arrive earlier, frequently around 36 to 37 weeks. It is sensible to be ready a few weeks before the date.

Pregnancy week calculator: how far along am I?

Pregnancy week calculator

Your due date

An estimate, worked out in your browser. Nothing you enter is sent anywhere.

How far along you are

A pregnancy is counted from the first day of your last period, so "40 weeks" is measured from about two weeks before conception. This tool works your current week out from your due date, which sits 40 weeks from that start.

A countdown, not a deadline

Very few babies arrive exactly on their due date, and twins are usually earlier. Use the number to follow along and to plan, but keep some room around it, especially if you are expecting more than one.

Quick answer

This pregnancy week calculator works backwards from your due date to show how many weeks and days pregnant you are today, and how long is left. It runs in your browser. Dates are estimates, and twins often arrive earlier than a single baby, so treat the countdown as a guide.

How to use it

Enter your due date. Set your estimated due date. If you do not know it, work it out with the due date calculator first.
Read how far along you are. You get your current week and day, and the days remaining.
Remember it is an estimate. Dating scans and your midwife give the figure to go by; twins often come earlier.

Frequently asked questions

How many weeks pregnant am I?: Counting from the first day of your last period, a full-term pregnancy is about 40 weeks. This tool works out your current week from your due date, which is 40 weeks from that start.
Why does the count use my due date?: Your due date is anchored to the start of pregnancy, so counting back from it gives a consistent current week. If your due date changed after a scan, use the updated date.
When will twins arrive?: Twins share the same estimated due date but very often arrive earlier, frequently around 36 to 37 weeks. It is sensible to be ready a few weeks before the date.