Pregnancy Calculator
Find out how many weeks pregnant you are and what trimester you're in.
Calculate Your Pregnancy Week
Your Pregnancy Details
Weeks pregnant—
Days into current week—
Current trimester—
Due date—
How pregnancy weeks are calculated
Pregnancy is counted from the first day of your last menstrual period (LMP), not from conception. Most pregnancies last 280 days or 40 weeks.
From LMP:
From conception:
Trimesters: 1st (weeks 1-12), 2nd (weeks 13-26), 3rd (weeks 27-40+)
Due date = LMP + 280 daysFrom conception:
Due date = Conception date + 266 daysTrimesters: 1st (weeks 1-12), 2nd (weeks 13-26), 3rd (weeks 27-40+)
FAQs
How accurate is this calculator?
It gives a good estimate, but only an ultrasound can accurately date your pregnancy.
Why is pregnancy counted from my last period?
It's easier to remember your last period date than conception date. This is the medical standard.
What if I don't know my LMP?
Use the conception date method if you know when you conceived, or see a doctor for an ultrasound.
When are the trimesters?
1st trimester: weeks 1-12. 2nd trimester: weeks 13-26. 3rd trimester: weeks 27-40+.
Is my due date exact?
No, only about 5% of babies are born on their due date. Most babies arrive within 2 weeks before or after.