Pregnancy week calculator by lmp

How many weeks pregnant am I?

To determine your due date, healthcare providers count 40 weeks from the first day of your last menstrual period (LMP) rather than trying to guess exactly when sperm met egg.

(You can use our Pregnancy Due Date Calculator to check how many weeks pregnant you are!)  

Healthcare providers use your LMP to date pregnancy because many women don't know which day they ovulated. And even if you know the day you had sex that resulted in pregnancy, that may not be the day you conceived: Sperm can linger in your uterus for up to five days waiting for an egg to be released so they can fertilize it.

Using your LMP to find your due date means that when you get confirmation that you're pregnant, you'll most likely be 4 or 5 weeks along.

How many weeks are in a pregnancy?

There are 40 weeks in a pregnancy – though you're just as likely to deliver your baby a few weeks before or after that.

How many weeks are in a trimester?

Each trimester is about 13 weeks

how to count your weeks pregnant

how to count my weeks of pregnancy