Pregnancy Due Date & Weeks Calculator

Calculate your expected delivery date and the current number of weeks and days of your pregnancy based on the first day of your last menstrual period.

First day of last menstrual period

Calculation Result

Expected Due Date

2026-12-09

Current Progress

0weeks0days

Trimester

First Trimester

Days until due date

280days

How to Use

STEP 1
Select or input the first day of your last menstrual period (LMP) from the calendar.
STEP 2
The expected due date and your current pregnancy progress (weeks and days) will be displayed immediately.

Calculated based on Naegele's rule, assuming a 28-day menstrual cycle and ovulation on day 14.
The actual due date is just an estimate, and only about 5% of babies are born on their exact due date.

FAQ

Q1
What is the basis for this calculation?
It uses the standard method of setting the first day of your last period as '0 weeks 0 days' and the due date exactly 280 days (40 weeks) later.
Q2
How do I calculate for IVF?
You can back-calculate a 'fictional' LMP based on the transfer date and embryo age (e.g. Day 3 embryo is Pregnancy Week 2 Day 3).

Feedback (Contact)