BMI Calculator
Calculate BMI, weight category, healthy weight range, and target weight with clear visuals.
Background
Body Mass Index compares weight with height using BMI = weight / height². It is a quick adult screening tool, not a complete health assessment.
How to use this calculator
- Choose US or Metric units.
- Enter height and weight. In US mode, formats like 5'7, 5 ft 7 in, and 67 in are supported.
- Click Calculate BMI to see your BMI, category, healthy range, visual gauge, and steps.
- Use quick examples to test common inputs.
Formula and categories
BMI formula: BMI = weight(kg) / height(m)²
US shortcut: BMI = 703 × weight(lb) / height(in)²
General adult categories: underweight < 18.5, healthy 18.5–24.9, overweight 25–29.9, obesity ≥ 30.
Healthy weight range: weight = BMI × height², using BMI 18.5 to 24.9.
Example problems and step-by-step solutions
Example 1: 5'7, 145 lb
Height = 67 in. BMI = 703 × 145 / 67² ≈ 22.7, which falls in the healthy range.
Example 2: 170 cm, 65 kg
Height = 1.70 m. BMI = 65 / 1.70² ≈ 22.5, which falls in the healthy range.
Example 3: 5'10, 210 lb
Height = 70 in. BMI = 703 × 210 / 70² ≈ 30.1, which falls in the obesity category by general adult BMI cutoffs.
What BMI can and cannot tell you
BMI is useful as a quick screening number, but it does not directly measure body fat, muscle mass, bone density, body composition, pregnancy status, or individual medical risk. Athletes and people with higher muscle mass may have a high BMI without the same health implications.
FAQ
Can I enter height as 5'7?
Yes. In US mode, this calculator accepts 5'7, 5’7”, 5 ft 7 in, or 67 in.
What BMI is considered healthy?
For most adults, BMI 18.5 to 24.9 is commonly classified as the healthy range.
Is BMI accurate for everyone?
No. BMI is a screening tool and does not distinguish muscle from fat or account for all individual differences.
All calculators