See how far along you are. This free pregnancy calculator shows your weeks pregnant, trimester, due date and progress, calculated from your last period, due date or conception date.
This shows roughly how far along a pregnancy is, for general information. Gestational age is measured from the first day of the last period, so it’s about two weeks more than the time since conception. Your midwife or doctor’s dating scan is the most accurate guide.
Calculate from
days
Enter the relevant date and the calculator shows how many weeks and days pregnant you are today, your trimester, due date and progress.
How far along (today)
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Enter a date
Trimester
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Progress
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Due date
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Days to go
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Estimates only and not medical advice. Confirm your dates and follow your antenatal care with a qualified midwife or doctor.
Use this free pregnancy calculator to find out how far along you are. Enter your last period, due date or conception date to see your weeks pregnant, trimester, due date and progress.
What this pregnancy calculator does
A pregnancy calculator tells you how many weeks pregnant you are today (your gestational age), which trimester you’re in, your estimated due date, and how much of the roughly 40-week journey is complete.
How “weeks pregnant” is measured
Gestational age = days since the first day of your last period
Weeks pregnant = gestational age ÷ 7
Pregnancy is dated from the last period, not conception — so “weeks pregnant” is about two weeks more than the time since conception. A full-term pregnancy is around 40 weeks.
The three trimesters
Trimester
Weeks
First
1 – 13
Second
14 – 27
Third
28 – 40+
Dating from last period, due date or conception
If you know your due date, the calculator works backwards to your current week. If you know a conception date, it adds about two weeks to estimate gestational age. The last period method is the standard clinical approach.
How to use the pregnancy calculator
Choose your starting point — last period, due date or conception.
Enter the date (and cycle length for the last-period method).
Read how far along you are, your trimester and progress.
Pregnancy FAQ
How do I know how many weeks pregnant I am?
Count the days from the first day of your last period to today, then divide by 7. The calculator shows your weeks and days, since pregnancy is dated from the last period.
Why is pregnancy dated from the last period, not conception?
Because the last period is a known date, while the exact conception day usually isn't. This makes "weeks pregnant" about two weeks more than the time since conception.
What trimester am I in?
First trimester is weeks 1–13, second is 14–27, and third is 28 onward. The calculator labels your current trimester automatically.
Can I calculate from my due date instead?
Yes. Switch to "due date" mode and it works backwards to your current week. There's also a conception-date option.
How accurate is it?
It's a useful estimate, but a dating ultrasound and your midwife or doctor give the most accurate measurement, especially with irregular cycles.
Is the pregnancy calculator free?
Yes, this pregnancy calculator is completely free, needs no sign-up, and gives instant results in your browser.
