Source: World Health Organization. BMI is a screening tool, not a diagnostic measure. Consult a healthcare provider for personalized guidance.
Frequently asked questions
What is a healthy BMI for adults? ›
According to the World Health Organization (WHO), a healthy BMI for adults is between 18.5 and 24.9. A BMI below 18.5 is considered underweight, 25–29.9 is overweight, and 30 or above is obese. These are population-level guidelines — an individual's optimal BMI may vary based on age, muscle mass, bone density, and ethnicity.
How is BMI calculated? ›
BMI = weight (kg) ÷ height (m)². In US units: BMI = (weight in lbs × 703) ÷ (height in inches)². For example, someone 5'10" tall (70 in) weighing 175 lbs: BMI = (175 × 703) ÷ (70²) = 123,025 ÷ 4,900 ≈ 25.1. The formula is the same for men and women and doesn't directly account for age, muscle mass, or body fat distribution.
What are the limitations of BMI? ›
BMI doesn't distinguish between muscle and fat mass — athletes and very muscular people often have a high BMI despite being very healthy. It also doesn't account for where fat is distributed (abdominal fat is more health-risky than fat elsewhere), age (older adults naturally have more fat at the same BMI), or ethnicity (Asian populations have higher health risks at lower BMI values). The CDC recommends using BMI alongside waist circumference and other measures for a fuller health picture.
Is a BMI of 25 overweight? ›
Technically yes — the WHO defines BMI ≥ 25 as overweight. However, a BMI of 25.0 is right at the boundary, and whether this represents a meaningful health risk depends on individual factors including muscle mass, age, and family health history. Many researchers argue the 25 cutoff is somewhat arbitrary. A BMI of 25–27 is generally considered a modest risk increase, not a dramatic one. Consult your doctor for a personalized interpretation.
About this BMI calculator
This calculator uses the standard WHO BMI formula: weight in kilograms divided by height in meters squared. In US units it applies the conversion factor of 703 (pounds × 703 ÷ inches²). It shows your BMI on a visual gauge, identifies your category, calculates your healthy weight range for your height, and shows how many pounds or kilograms you'd need to gain or lose to reach a normal BMI — all instantly, no sign-up required.
BMI is a useful population-level screening tool but is not a substitute for medical advice. If you have concerns about your weight or health, please speak with a qualified healthcare provider.