BMI (Imperial)
BMI using pounds and inches.
Formula
Live Calculator
MembersVariables
Example
154 lb, 69 in ⇒ 22.7
How it works
Body Mass Index (BMI) is a quick screening measure that compares a person’s weight to their height, giving a single number that can be used to flag possible underweight, healthy-weight, overweight, or obesity ranges. In the imperial version, the factor 703 converts the units so pounds and inches produce the same kind of ratio used in the metric formula. It works because it scales mass by height squared, which helps account for the fact that taller people naturally weigh more.
When to use it
Use this formula when you need a fast estimate of BMI from measurements taken in pounds and inches, such as in a clinic, fitness app, or health worksheet. It is useful for screening, but it does not replace a full medical assessment because it cannot distinguish muscle from body fat.
Worked example, step by step
Given mass = 180 lb and height = 70 in Step 1: Square the height: 70^2 = 4900 Step 2: Multiply the mass by 703: 703 × 180 = 126540 Step 3: Divide by the squared height: 126540 ÷ 4900 = 25.824... Step 4: Round to one decimal place: BMI = 25.8
Common mistakes to avoid
- Forgetting to square the height before dividing
- Using kilograms or centimeters with the imperial formula
- Rounding too early and getting an inaccurate final BMI
Did You Know?
The imperial BMI formula needs a factor of 703 just to reconcile pounds and inches with the original metric version.
Share this formula
More in Health & Fitness
View allBody Mass Index (BMI)
BasicWeight-to-height ratio used to classify body weight.
BMR (Mifflin, Men)
IntermediateBasal metabolic rate — daily calories at rest for men.
BMR (Mifflin, Women)
IntermediateBasal metabolic rate for women.
Total Daily Energy (TDEE)
IntermediateDaily calories burned including activity.
Max Heart Rate
BasicEstimated maximum heart rate by age.
Target Heart Rate (Karvonen)
AdvancedTraining heart rate at intensity I.