What is the Weight for Height Calculator?
This calculator estimates the healthy body weight range for an adult of a given height, based on the World Health Organization's standard body mass index (BMI) classification. A BMI between 18.5 and 25 is generally considered the normal, healthy range, so this tool converts those BMI limits into actual kilogram values for your height.
How to use it
Choose whether you want to enter your height in centimeters or inches, type your height, and the calculator returns the lower bound (BMI 18.5), midpoint (BMI 21.75), and upper bound (BMI 25) of your healthy weight range in kilograms.
The formula explained
BMI is defined as weight in kilograms divided by height in meters squared: \(\text{BMI} = W / h^{2}\). Rearranging for weight gives \(W = \text{BMI} \times h^{2}\). Using the healthy BMI limits, the lower bound is \(18.5 \times h^{2}\) and the upper bound is \(25 \times h^{2}\), where h is your height in meters. Inches are converted with 1 inch = 0.0254 m and centimeters with 1 cm = 0.01 m.
$$\text{Healthy Weight} = \text{BMI} \times h^{2}$$
Worked example
For a height of 70 inches: h = 70 × 0.0254 = 1.778 m, so h² = 3.161284. The lower bound is 18.5 × 3.161284 ≈ 58.48 kg and the upper bound is 25 × 3.161284 ≈ 79.03 kg. A healthy weight for someone 70 inches tall is therefore roughly 58–79 kg.
$$h = 70 \times 0.0254 = 1.778 \;\text{m}$$$$h^{2} = 3.161284$$$$18.5 \times 3.161284 \approx 58.48 \;\text{kg}$$$$25 \times 3.161284 \approx 79.03 \;\text{kg}$$FAQ
Is this an exact ideal weight? No. It is a population-level range, not a personalized target. Muscle mass, frame size, age, and sex all affect what is healthy for an individual.
Why a range instead of one number? Because the healthy BMI band itself spans 18.5 to 25, every height maps to a band of acceptable weights rather than a single value.
Does it work for children? No. BMI cutoffs for children and teens use age- and sex-specific percentiles, so this adult tool is not appropriate for under-18s.
