Fitness & Health

BMI Calculator

Body mass index with quick category feedback.

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Inputs

BMI uses height and weight to estimate body mass for adults.

SexAgeTarget BMI

Weight (kg)Height (cm)

Results

BMI categories are general guidelines for adults.

Body mass index

22.86

BMI	Weight
18.5	56.66 kg
25	76.56 kg
30	91.88 kg
35	107.19 kg

BMI classifications

Category	BMI range
Underweight	< 18.5
Normal	18.5 - 24.9
Overweight	25 - 29.9
Obesity	30+

BMI is a screening metric, not a diagnosis. Consider body composition and overall health.

References

World Health Organization BMI classification
CDC BMI guidance for adults and children
US Navy and academic references for Ponderal Index

How this calculator works

Calculates body mass index from height and weight and classifies the result for adults. It also provides BMI Prime, Ponderal Index, and a healthy weight range based on height so you can interpret the result with more context.

Inputs

Height and weight in Metric, US, or Other units
Age and sex for context
Unit selection and conversions

Outputs

BMI value and category
Healthy weight range for the given height
BMI Prime and Ponderal Index
BMI scale position

Assumptions

Adult BMI categories are screening guidelines
Children and teens require age- and sex-specific charts
BMI does not directly measure body fat

Tips

Use consistent units for better accuracy
Consider waist and body composition for more context
Track trends over time rather than a single value

BMI = weight(kg) / height(m)^2

BMI Prime = BMI / 25

Ponderal Index = weight(kg) / height(m)^3

Healthy Range = 18.5-24.9 * height(m)^2

Usage examples

Copy a scenario, then tweak inputs to match your case.

Example

Metric example

Inputs

Weight 70 kg and height 175 cm
Age 30 with adult category

Outputs

BMI about 22.9 and Normal category
Healthy range about 56 to 76 kg

Uses standard adult categories for interpretation.

Example

US example

Inputs

Weight 154 lb and height 5 ft 9 in
Age 30 with adult category

Outputs

BMI about 22.7 and Normal category
BMI Prime about 0.91

Same outcome with different units and conversions.

Adult BMI categories

Category	Range
Underweight	< 18.5
Normal	18.5 - 24.9
Overweight	25 - 29.9
Obesity	30+

Categories apply to adults and are not diagnostic.

BMI points on scale

CategoryBMI value

PositiveNegative

Under

Normal

Over

Obese

Sample values placed within each category band.

BMI is a screening tool and not a diagnosis.

References

World Health Organization BMI classification
CDC BMI guidance for adults and children
Ponderal Index background

FAQ

Common questions

What does the BMI Calculator do?

What inputs do I need?

Typical inputs include Height and weight in Metric, US, or Other units, Age and sex for context, Unit selection and conversions.

How are the results calculated?

We follow the formulas and assumptions outlined in the "How this calculator works" section. You will see outputs like BMI value and category, Healthy weight range for the given height, BMI Prime and Ponderal Index.