BMI Calculator
Estimate your Body Mass Index from height and weight
Healthy weight for your height:
BMI Calculator — Complete Guide & Instructions
MakeCard BMI Calculator gives your Body Mass Index the moment you stop typing — no submit button required. Switch between Metric (cm/kg) and Imperial (ft/in) units, enter height and weight, and watch your BMI appear with its WHO category badge on a colour gradient scale from 14 to 40. It also converts the healthy BMI range back into an actual kilogram range for your height, which is far more actionable than a bare number.
How to Use BMI Calculator
- 1 Pick “Metric (cm/kg)” or “Imperial (ft/in)” using the toggle buttons.
- 2 Enter your height — centimetres, or feet plus inches.
- 3 Enter your weight in kilograms.
- 4 Read your BMI score and the colour-coded category badge below.
- 5 Check where the marker sits on the 14–40 scale and note your healthy weight range in kg.
Key Features & Capabilities
- Metric and Imperial input modes — no manual unit conversion needed.
- Live BMI computation as you type.
- WHO category badge with an explanatory note.
- Gradient meter from 14 to 40 showing exactly where you sit.
- Healthy weight range in kg calculated for your specific height.
- Clean, mobile-friendly layout for gym-side checks.
Supported Formats & Specifications
| Parameter | Specification |
|---|---|
| Units | Metric (cm, kg) or Imperial (ft + in, kg) |
| Formula | BMI = weight(kg) ÷ height(m)² |
| Scale shown | 14 – 40 with markers at 18.5, 25 and 30 |
| Output | BMI value, category, healthy weight range |
| Processing | Instant, in-browser |
Practical Everyday Use Cases
- A quick health baseline check before starting a diet or gym plan.
- Tracking BMI change month over month during weight loss.
- Screening numbers needed for insurance or medical forms.
- Checking whether a weight goal lands inside the healthy band for your height.
- Comparing metric and imperial entries when a form uses the other system.
Pro Tips for Best Results
- BMI is a screening number, not a diagnosis — muscular athletes often score “overweight” while being perfectly healthy.
- Measure height barefoot and weight in light clothing, morning, for consistent readings.
- The healthy weight range box converts 18.5–24.9 BMI into real kilograms — use it as your target zone.
- Pair with the BMR calculator to plan a calorie target alongside the weight goal.
Common Problems & Solutions
Check the units toggle — entering 170 in the feet field produces a nonsense result; switch to Metric for cm/kg values.
BMI cannot distinguish muscle from fat — athletes should also track body-fat percentage or waist measurements.
Privacy & Security
100% Client-Side Execution
Height and weight never leave your browser — the calculation is fully local and nothing is stored.
Frequently Asked Questions
Everything you need to know about using BMI Calculator
WHO classifies 18.5–24.9 as the healthy range; below 18.5 is underweight, 25–29.9 overweight, and 30+ obese. The tool shows the category badge automatically.
Divide your weight in kilograms by your height in metres squared — for example 65 kg and 1.70 m gives a BMI of about 22.5.
It is a population-level screening tool — it underestimates risk in very lean people and overestimates it in muscular builds, so treat it as a starting point, not a verdict.
Yes — press the Imperial (ft/in) button and separate Feet and Inches fields appear.
The formula is identical; interpretation ranges are the same for adults, though women naturally carry a higher essential body-fat percentage.
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