BMI Calculator Formula
Understand the math behind the bmi calculator. Each variable explained with a worked example.
Formulas Used
BMI
bmi = (weight_lbs * 703) / (total_inches * total_inches)Variables
| Variable | Description | Default |
|---|---|---|
weight_lbs | Weight(lbs) | 170 |
height_feet | Height (feet)(ft) | 5 |
height_inches | Height (inches)(in) | 10 |
total_inches | Derived value= height_feet * 12 + height_inches | calculated |
How It Works
How BMI Is Calculated
Formula (Imperial)
BMI = (Weight in lbs x 703) / (Height in inches)^2
BMI Categories
| BMI | Category | |---|---| | Below 18.5 | Underweight | | 18.5 - 24.9 | Normal weight | | 25.0 - 29.9 | Overweight | | 30.0+ | Obese |
Worked Example
A person weighing 170 lbs at 5 feet 10 inches.
weight_lbs = 170height_feet = 5height_inches = 10
- 01Height in inches = 5 x 12 + 10 = 70 inches
- 02BMI = (170 x 703) / (70 x 70)
- 03= 119,510 / 4,900
- 04= 24.4 (Normal weight)
Ready to run the numbers?
Open BMI Calculator