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Start with a realistic example, adjust the inputs, or save your numbers before experimenting.
A 70 kilogram adult at 175 centimetres
Enter 175 centimetres of height and 70 kilograms of weight. That is a common adult pair and a useful first check of the formula.
Height: 25% lower
Change height to 131 cm while keeping the other example values the same.
Height: 25% higher
Change height to 219 cm while keeping the other example values the same.
Interactive chart
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Quick answer
What does the Body mass index calculate?
What body mass index follows from the height and weight you enter? This calculator uses height, and weight to estimate adult bmi screening number immediately in your browser.
With the values currently entered, the result is 22.9 — BMI, CDC adult healthy weight range. It also shows cdc adult category, height, weight, and height used in the formula.
How to use the Body mass index
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Height — entered in cm
- Weight — entered in kg
Body mass index formula
BMI = weight in kilograms ÷ (height in metres)²
Assumptions
- This uses the adult screening formula published by CDC: weight in kilograms divided by height in metres squared.
- CDC adult categories apply to people 20 and older. They are a screening measure, not a diagnosis.
Verify the inputs
Authoritative sources
These sources explain the definitions, factors, or rules behind this tool. Their geographic scope is shown because an official source for one country is not automatically valid somewhere else.
Sources do not endorse Calculum. Check the source date, scope, and your own documents before making a financial, tax, insurance, or reporting decision.
Practical guide
Body mass index example and edge cases
BMI is weight divided by height squared. CDC uses it as an adult screening number, not as a diagnosis of health.
Example: A 70 kilogram adult at 175 centimetres
Enter 175 centimetres of height and 70 kilograms of weight. That is a common adult pair and a useful first check of the formula.
- Height
- 175 cm
- Weight
- 70 kg
Calculated result22.9BMI, CDC adult healthy weight range
Read the category next to the number. Then look at the related calorie calculator if you want an energy estimate from the same size.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- CDC adult categories start at 20 years old. A child or teen needs a percentile chart, not this number.
- Muscle, bone, and where fat sits can move health risk without moving BMI much. Treat 22.9 as a screen, not a verdict.
Edge cases worth checking
The person is under 20
Stop here and use a pediatric BMI-for-age chart. Adult cutoffs do not apply to children.
Height was taken in shoes
Shoes add height and pull BMI down. Measure without them so the ratio matches the CDC method.
What changes the result most
Height
Measure height with the same unit shown beside the input. Convert first if your source uses another unit.
Weight
Measure weight with the same unit shown beside the input. Convert first if your source uses another unit.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Height: 25% lower
131 cm40.8BMI, CDC adult obesity range
Height: 25% higher
219 cm14.6BMI, CDC adult underweight range
Weight: 25% higher
88 kg28.7BMI, CDC adult overweight range
Common mistakes
Check height
This uses the adult screening formula published by CDC: weight in kilograms divided by height in metres squared. Make sure this matches the number you enter.
Keep weight consistent
CDC adult categories apply to people 20 and older. They are a screening measure, not a diagnosis. Use the same units and time period throughout the calculation.
Do not rely on one body mass index scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
What body mass index follows from the height and weight you enter?
Use it for activity planning, not medical diagnosis or individualized health advice.