See how many weeks and days pregnant you are, your trimester, your baby’s size, days to go and upcoming milestones such as scans and full term.
About this tool
See how many weeks pregnant you are, your trimester and key milestones.
How to use Pregnancy Week Calculator
- Choose what to calculate from and enter the date.
- Read how far along you are, your trimester and progress.
- Check the milestone dates in the table.
Worked example
Seventeen weeks after the last period you are in the second trimester, and the baby is about the size of a sweet potato.
When do pregnancy weeks start?
From the first day of the last period, about two weeks before conception.
When are the trimesters?
The first runs to the end of week 13, the second to the end of week 27, and the third until birth.
Explore Health & Body Calculators · More practical guides