how to compute bmi

To compute BMI, you divide weight by height squared, using the right units for each formula.

How to Compute BMI (Quick Scoop)

1. The basic BMI formulas

Metric formula :
BMI=weight (kg)[height (m)]2\text{BMI}=\dfrac{\text{weight (kg)}}{[\text{height (m)}]^2}BMI=[height (m)]2weight (kg).

Metric with height in cm :
BMI=weight (kg)[height (cm)]2×10,000\text{BMI}=\dfrac{\text{weight (kg)}}{[\text{height (cm)}]^2}\times 10{,}000BMI=[height (cm)]2weight (kg)×10,000.

US / imperial units :
BMI=weight (lb)[height (in)]2×703\text{BMI}=\dfrac{\text{weight (lb)}}{[\text{height (in)}]^2}\times 703BMI=[height (in)]2weight (lb)×703.

The key idea is that BMI is weight relative to height , adjusted so you get a single number you can compare to standard ranges.

2. Step‑by‑step: BMI with metric units

Example: weight = 70 kg, height = 1.75 m.

Convert height to meters if needed (e.g., 175 cm → 1.75 m).

Square the height:
height2=1.75×1.75=3.0625\text{height}^2=1.75\times 1.75=3.0625height2=1.75×1.75=3.0625.

Divide weight by height²:
BMI=70÷3.0625≈22.9\text{BMI}=70\div 3.0625\approx 22.9BMI=70÷3.0625≈22.9.

Round to 1 decimal place (22.9).

This BMI (about 22.9) falls in the usual “normal” or “healthy” range of 18.5–24.9.

3. Step‑by‑step: BMI with US/imperial units

Example: weight = 150 lb, height = 65 in.

Make sure height is total inches (e.g., 5 ft 5 in → 5×12+5=655\times 12+5=655×12+5=65 in).

Square the height in inches:
652=422565^2=4225652=4225.

Divide weight by height²:
150÷4225≈0.0355150\div 4225\approx 0.0355150÷4225≈0.0355.

Multiply by 703:
0.0355×703≈24.90.0355\times 703\approx 24.90.0355×703≈24.9.

Round to 1 decimal place if you like (24.9).

4. BMI categories (for adults)

Typical adult BMI ranges used by major health organizations:

Underweight: below 18.5
Normal (healthy) weight: 18.5 to 24.9
Overweight: 25.0 to 29.9
Obesity: 30.0 or higher

These cut‑offs are general screening ranges, not a full health diagnosis.

5. Mini FAQ and caveats

Is BMI a perfect measure?
No. BMI doesn’t distinguish muscle from fat, ignore body composition, and doesn’t include things like fitness level or metabolic health.

Does ethnicity matter?
Some groups (for example, many Asian populations) may have higher health risks at lower BMI values, so risk interpretation can shift slightly.

How should I use BMI?
Use it as a screening tool or rough guide, and talk with a health professional for personal advice, especially if your BMI is outside the “normal” range or you have other risk factors.

HTML table: BMI formulas at a glance

html

<table>
  <thead>
    <tr>
      <th>System</th>
      <th>Formula</th>
      <th>Example Inputs</th>
      <th>Result (BMI)</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Metric (m)</td>
      <td>BMI = weight (kg) / [height (m)]² [web:1][web:3][web:5][web:9]</td>
      <td>70 kg, 1.75 m [web:4]</td>
      <td>≈ 22.9 [web:4][web:6]</td>
    </tr>
    <tr>
      <td>Metric (cm)</td>
      <td>BMI = weight (kg) / [height (cm)]² × 10,000 [web:5]</td>
      <td>70 kg, 175 cm</td>
      <td>≈ 22.9 [web:5][web:6]</td>
    </tr>
    <tr>
      <td>US / Imperial</td>
      <td>BMI = weight (lb) / [height (in)]² × 703 [web:3][web:5][web:7]</td>
      <td>150 lb, 65 in [web:4][web:7]</td>
      <td>≈ 24.9 [web:4][web:7]</td>
    </tr>
  </tbody>
</table>

TL;DR:
Take your weight, divide by your height squared (using the correct units), and compare the number to standard BMI ranges—just remember it’s a screening tool, not a full verdict on your health.

Information gathered from public forums or data available on the internet and portrayed here.

how to compute bmi