Crunch BMI Calculator
Enter your height and weight to get your Body Mass Index and see which category you fall into. Switch between imperial and metric anytime.
| Category | — |
| Healthy weight range for your height | — |
How it works
Imperial: BMI = 703 × weight (lbs) ÷ height (in)2. Metric: BMI = weight (kg) ÷ height (m)2. Categories follow CDC cutoffs: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese.
Formula & worked example
Formula: BMI = 703 × weight (lb) ÷ height (in)², or weight (kg) ÷ height (m)². Categories: under 18.5 underweight, 18.5–24.9 healthy, 25–29.9 overweight, 30+ obese.
Worked example: At 180 lb and 5′10″ (70 in): 703 × 180 ÷ 4,900 = 25.8 — just inside the overweight band.
Frequently asked questions
What is a healthy BMI?
The CDC defines a healthy BMI as 18.5 to 24.9 for adults. Athletes with high muscle mass may score above 25 while still being healthy.
How accurate is BMI?
It's a quick population-level screen, not a body-fat measurement. Two people with the same BMI can have very different health profiles.
Should I convert my units first?
No — just pick Imperial or Metric above and enter your numbers as-is. The tool converts behind the scenes.
📊 Want the full picture?
Pair your BMI with your savings and health goals — our compound interest and savings goal calculators do the money math.