Lifestyle tools

BMI Calculator

Enter your height and weight to see BMI and adult category results. Results are for health reference only and do not replace medical diagnosis.

🧍cm

Example: 170 cm

⚖️kg

Example: 65 kg

🛡 This tool is for reference only. Consult a professional for pregnancy, athletes, children, or special medical conditions.

Your BMI
22.9
Healthy range
In good condition!
Friendly ToolBoy health character
UnderweightHealthyOverweightObesity
18.52427

Healthy weight range

56.7~73.5kg
Calculated based on height 175 cm

Suggested weight 👨

66.5 kg
Male formula: (height −80)×0.7
My current weight is within a healthy range, keep it up!

A reminder

Balanced diet + regular exercise = healthy life

Waist circumference reference: men should be less than 90 cm

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Metric and imperial units
Switch units with ease
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Standard-based categories
Taiwan / WHO standards
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Visual indicator
See your result at a glance
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ToolBoy is here to help
A friendly way to understand health

How to use the BMI calculator

1

Enter your height

Enter centimetres, or use feet and inches.

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2

Enter your weight

Kilograms and pounds are converted automatically.

⚖️
3

Choose a standard

Choose the Taiwan adult or WHO international category.

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4

View your result

Get your BMI, category, and healthy-weight range instantly.

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About body mass index (BMI)

BMI (Body Mass Index) uses height and weight to estimate whether weight is within a general healthy range. It is suitable for an initial adult self-check.

BMI = weight (kg) ÷ height (m)²

Adult BMI categories (Taiwan)

CategoryBMI range
UnderweightBMI < 18.5
Healthy18.5 ≤ BMI < 24
Overweight24 ≤ BMI < 27
ObesityBMI ≥ 27
ToolBoy reading health information

Frequently asked questions

Does BMI differ by sex?

The BMI formula and adult categories are the same for all sexes. Body-fat and muscle proportions may differ, so this tool also provides an ideal-weight and waist-size reference.

Is BMI accurate?

BMI is a useful initial adult screening tool, but it cannot distinguish fat from muscle and does not replace a full health assessment.

Is BMI less accurate for muscular people?

It can be. Athletes with more muscle may have a higher BMI without having high body fat. Consider body-fat percentage and waist size too.

Can children use adult BMI directly?

No. Children and teenagers should use growth charts based on age and biological sex.

How often should I measure BMI?

For most people, recording it monthly at a consistent time is enough. Follow professional advice when managing health conditions.

How is ideal weight calculated?

A common method works back from a BMI of 22. This tool also uses a height- and sex-based reference formula to show a suggested weight.

Is the BMI calculation used in physical examinations the same?

Yes. BMI is weight divided by height squared. Organisations may use different ranges to interpret the same value.

How is ideal weight calculated?

Ideal weight is often estimated with either of these two methods:

BMI 22 method: ideal weight = 22 × height (m)²

This method works back from BMI 22, the middle of the healthy range, and is useful as a long-term target for adults.

Height-and-sex reference: men = (height − 80) × 0.7; women = (height − 70) × 0.6

This is a reference formula expressed in kilograms. The suggested weight shown by this page changes with the selected sex.

Ideal weight is only a reference. A sustainable healthy range and overall health matter more than reaching one particular number.

What if BMI is high or low?

BMI ≥ 24 (overweight) or ≥ 27 (obesity)

Avoid drastic dieting. Start with regular activity, balanced meals, adequate sleep, and a gradual weight goal. Waist measurement can provide useful additional context.

BMI < 18.5 (underweight)

Low weight can be associated with inadequate nutrition and other health concerns. Eat regular meals, include quality protein, and seek medical advice if weight changes noticeably without intent.

When should I seek medical advice?

Consult a health professional for severe obesity, related health conditions, sleep-disordered breathing, or substantial unintentional weight change.

Common uses of BMI

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Physical examinations

BMI may be used together with height in physical-examination standards; confirm the applicable standard with the relevant organisation.

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Student fitness

Schools may calculate BMI as one basic physical-fitness and health-management measure.

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Health-check reports

A BMI outside the recommended range on a health report can help you set a gradual, practical weight goal.

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Weight and fitness goals

Use BMI together with waist size and body-fat percentage to set a more useful goal than a single target weight.

Popular searches

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