BMI Calculator (Imperial)

What is an Imperial BMI Calculator?

An imperial BMI calculator computes body mass index using the imperial measurement system: feet, inches, and pounds. The formula is: BMI = (weight in pounds × 703) ÷ (height in inches)². This calculator is particularly convenient for US residents and others using the imperial system.

How to Use the Imperial BMI Calculator

1. Enter your height in feet (e.g., 5 feet)
2. Add the inches (e.g., 10 inches)
3. Input your weight in pounds (e.g., 190 pounds)
4. Click the "Calculate" button

BMI Categories in Imperial System

• Underweight: BMI less than 18.5
• Normal weight: BMI 18.5-24.9
• Overweight: BMI 25.0-29.9
• Obesity Class I: BMI 30.0-34.9
• Obesity Class II: BMI 35.0-39.9
• Obesity Class III: BMI 40.0 and above

Example BMI Calculation in Pounds and Feet

Example: Height 5 feet 10 inches (70 inches), weight 190 pounds:

BMI = (190 × 703) ÷ (70 × 70) = 133570 ÷ 4900 ≈ 27.26

The result indicates overweight status.

Benefits of Imperial BMI Calculator

• Familiar measurement units for Americans
• Accurate calculation using the 703 conversion factor
• Instant result categorization
• Healthy weight recommendations in pounds

Limitations of Imperial BMI Calculator

It's important to note that the imperial BMI calculator doesn't account for:

• Muscle-to-fat ratio and body composition
• Body frame size and constitution
• Age-related metabolic changes
• Individual genetic factors

Converting Between Imperial and Metric BMI

The 703 conversion factor bridges imperial and metric systems:

• 1 pound ≈ 0.453592 kg
• 1 inch = 2.54 cm
• 703 factor accounts for unit conversion in BMI formula

Common Imperial BMI Examples

Check the BMI for common height and weight combinations:

• 5'4" 120 lbs
• 5'6" 150 lbs
• 5'10" 175 lbs
• 6'0" 200 lbs
• 5'8" 220 lbs

Who the BMI Scale Applies To

The WHO categories on this page are for adults aged 18 and over, and they are the same for men and women: sex does not enter the BMI formula and does not move the category boundaries.

Children and teenagers aged 5–19 are read differently. Their BMI is compared with a WHO reference for age and sex and expressed as a z-score (SDS; WHO publishes the same reference as percentile charts): overweight above +1 SD, obesity above +2 SD, thinness below −2 SD and severe thinness below −3 SD. At the top of that range the two scales meet — WHO notes that +1 SD equals a BMI of 25 at 19 years, and +2 SD equals 30. WHO BMI-for-age (5–19 years)

For older adults the WHO classification above draws no separate line by age. Other guidance does, for a different purpose: the ESPEN consensus on diagnosing malnutrition counts a BMI as reduced below 20 under the age of 70 and below 22 above it. On its own that is not a diagnosis: there it only counts alongside mandatory unintentional weight loss. It is a boundary inside a diagnostic criterion, not a healthy weight range, and this page does not apply it. ESPEN Consensus Statement, Clinical Nutrition, 2015