Pregnancy Week Calculator
How many weeks pregnant you are, your trimester, your baby's approximate weight and the key check-ups ahead.
Result
How to use
- 1
Choose whether you know the first day of your last period or your due date.
- 2
Pick the date.
- 3
See your week of pregnancy, trimester and the milestones and tests coming up.
Questions
How are pregnancy weeks counted?
Doctors count from the first day of your last menstrual period (LMP), about two weeks before conception. A full-term pregnancy is about 40 weeks (280 days) from the LMP. If an early ultrasound gave you a different due date, use that due date here.
When does each trimester start?
The first trimester runs to the end of week 13, the second from week 14 to the end of week 27, and the third from week 28 until birth. Babies born from 39 weeks 0 days to 40 weeks 6 days are 'full term'.
How accurate is the baby's weight?
The weights shown are typical averages from ultrasound growth charts (Hadlock, 1991). Every baby grows differently and many healthy Indian babies are a little smaller — your doctor's scans are the best guide.
About this Pregnancy Week tool
Pregnancy Week Calculator — How many weeks pregnant you are, your trimester, your baby's approximate weight and the key check-ups ahead. It is one of 200 free tools on namasivayam.in, made by software engineer Namasivayam Vadivelan for everyday use in India.
Everything is calculated instantly in your browser: nothing you type or upload is sent to any server, there is no sign-up, and it works on mobile and desktop. Choose whether you know the first day of your last period or your due date.
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Results are estimates to help you plan. They are not financial, tax or medical advice.