Health & Fitness

BMI Calculator

Calculate Body Mass Index and understand your weight category.

BMI is a widely-used screening tool that uses height and weight to estimate body fat. While it has limitations (it cannot distinguish fat from muscle), it remains a useful first indicator of weight-related health risk.

Enter your numbers

Weight (lbs)

Height (inches)

5'10" = 70 inches.

Results update as you change the inputs. Calculations run in your browser.

BMI — Normal Weight

24.4

healthy Range: 129-174 lbs
classification: Normal Weight
note: BMI is a screening tool only

See the formula

Formula and method

BMI = (Weight in lbs / Height in inches²) × 703

Standard CDC formula for BMI using imperial units. WHO categories: <18.5 Underweight, 18.5-24.9 Normal, 25-29.9 Overweight, ≥30 Obese.

Worked examples

Average adult male

Weight (lbs):: 185
Height (inches):: 70

BMI — Overweight: 26.5

Athletic female

Weight (lbs):: 145
Height (inches):: 65

BMI — Normal Weight: 24.1

Assumptions and limits

Standard CDC/WHO BMI categories
Adult formula (18+)

This tool provides an educational estimate. Rules, rates and personal circumstances can change the answer. Review the assumptions before relying on a result. Report a correction.

Common mistakes to avoid

Treating BMI as a diagnostic tool — it is a screening metric only.
Applying BMI to athletes — high muscle mass elevates BMI without increased health risk.
Using BMI without considering waist circumference or other metabolic risk factors.

Frequently asked questions

Is BMI accurate for everyone?

BMI is a population-level screening tool. It overestimates risk for muscular individuals (athletes, bodybuilders) and underestimates risk for older adults who have lost muscle mass. Waist circumference and body fat percentage are more precise.

What is the BMI formula in metric?

In metric: BMI = weight(kg) / height(m)². For example, 70kg at 1.75m = 70 / (1.75 × 1.75) = 22.9.