Healthy Weight Calculator
Check your Body Mass Index (BMI) and healthy weight range by age and height, with a metric or imperial BMI category chart for adults.
Estimates for general guidance only — not medical advice. Check with a healthcare professional for personal decisions.
Also covers: accurate bmi calculator by age and gender with chart · adult body mass index category table · metric and imperial bmi tool
Formula & How It Works
BMI = weight(kg) ÷ height(m)² · imperial: 703 × weight(lb) ÷ height(in)²
- Both unit systems give the same BMI, so you can enter whichever measurements you have.
- The calculator works backwards from your BMI to a healthy weight range for your exact height, using 18.5 and 24.9 as the boundaries.
- BMI is a height-to-weight ratio only: it does not measure body fat, muscle mass, or where fat is carried.
Step-by-Step Example
70 kg at 173 cm.
- 1.Height in metres
- 173 ÷ 100 = 1.73 m
- 2.Square the height
- 1.73 × 1.73 = 2.9929
- 3.BMI
- 70 ÷ 2.9929 = 23.4
- 4.Healthy range
- 18.5 × 2.9929 to 24.9 × 2.9929
BMI 23.4 — the normal-weight band — with a healthy weight range of about 55.4 kg to 74.5 kg for that height.
Frequently asked questions
What is a healthy BMI range for adults?
For adults a BMI from 18.5 to 24.9 is classified as normal weight, below 18.5 as underweight, 25 to 29.9 as overweight, and 30 or above as obese. 70 kg at 173 cm gives a BMI of 23.4, so the healthy weight range for that height is roughly 55.4 kg to 74.5 kg.
Does BMI differentiate between muscle mass and fat?
No. BMI uses only height and weight, so a muscular athlete can register as overweight without carrying excess fat, and an older adult with low muscle mass can register as normal while carrying more fat. Treat it as a quick population-level screen, and pair it with body-fat or waist measurements for a fuller picture.
What is the standard formula for calculating BMI in metric and imperial?
In metric, BMI is weight in kilograms divided by height in metres squared. In imperial it is weight in pounds multiplied by 703, divided by height in inches squared. Both produce the same number, and this calculator converts between the two systems so you can enter whichever measurements you have.
About the Healthy Weight Calculator
Check your Body Mass Index (BMI) and healthy weight range by age and height, with a metric or imperial BMI category chart for adults.
It runs entirely in your browser — nothing you type is sent to a server — and the result updates as you edit the inputs. Estimates are for educational and informational purposes only; see ourdisclaimer.
Common searches
- body mass index
- weight
- overweight
- obesity
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