Pregnancy Calculator
Find out how many weeks pregnant you are, your trimester and your estimated due date — privately, in your browser.
What is Pregnancy Calculator?
This calculator estimates the current pregnancy week, the estimated due date (EDD) and the trimesters from the last menstrual period (LMP). It uses Naegele's rule: EDD = LMP + 280 days (40 weeks). Results are estimates — always confirm with your doctor or ultrasound.
How to use
- Pick the date of your last menstrual period (LMP).
- See the current pregnancy week and trimester.
- Estimated due date appears automatically.
- This is an estimate — only your doctor can confirm.
Frequently asked questions
How is the due date calculated?
The calculator uses Naegele's Rule: it adds 280 days (40 weeks) to the first day of your last menstrual period.
How accurate is the EDD?
It is an estimate — only about 4% of babies are born on the exact predicted date. Most arrive within 2 weeks before or after. Your doctor may adjust based on ultrasound.
What if I do not remember my LMP?
A first-trimester ultrasound gives a more accurate due date. Speak to your OB-GYN — this online estimator only works with the LMP method.