Your healthy weight range is not a single number, it's a band. Two people of the same height can both be perfectly healthy at noticeably different weights, which is why a range is more useful than one target figure.
This calculator uses the World Health Organization's standard healthy BMI cutoffs, 18.5 to 25, and works backwards from your height to show the lightest and heaviest weights that fall inside that band. It's a quick, evidence-based starting point for goal setting, whether you're losing, gaining, or maintaining.
How the healthy weight calculator works
The calculator only needs one input: your height. It returns a low-to-high weight range that corresponds to a BMI between 18.5 and 25, the standard "normal weight" band.
BMI is defined as weight in kilograms divided by height in metres squared (kg/m²). To find the weight range, the formula is rearranged to solve for weight:
- Low weight = 18.5 × height²
- High weight = 25 × height²
where height is in metres. In US units, height is taken in inches and the result is converted using the BMI constant of 703, so weight in pounds = (BMI × height in inches²) ÷ 703.
Enter your height in either metric (cm) or US (ft/in) units and the result updates live, showing the lower bound (BMI 18.5) and upper bound (BMI 25) of your healthy weight. Anything between those two numbers sits in the healthy BMI category for your height.
Worked example
Example: Someone who is 175 cm tall (1.75 m).
- Low end: 18.5 × 1.75² = 18.5 × 3.0625 = 56.7 kg
- High end: 25 × 1.75² = 25 × 3.0625 = 76.6 kg
So their healthy weight range is about 56.7 kg to 76.6 kg (roughly 125 to 169 lb). For a person who is 5'10" (70 inches), the same math in US units gives 18.5 × 70² ÷ 703 ≈ 128.9 lb to 25 × 70² ÷ 703 ≈ 174.3 lb.
Things to keep in mind
- BMI cutoffs of 18.5 to 25 are based on population averages and don't account for muscle mass, so very muscular people may read as 'overweight' while still being lean and healthy.
- The range uses height only and ignores body-fat distribution, bone density, age, sex, and ethnicity, factors that affect what weight is truly healthy for an individual.
- The 18.5 to 25 band is a general guideline; some health bodies use slightly different thresholds for certain populations (for example, lower upper limits for some Asian groups).
- This is a screening tool, not a diagnosis. A weight inside or outside the range doesn't confirm health or risk on its own, talk to a clinician for personal advice.
Frequently asked questions
What is a healthy weight range?
A healthy weight range is the band of weights that keep your BMI between 18.5 and 25 for your height. Instead of one target number, it gives a low and high figure, and any weight in between is considered a healthy BMI for that height.
How is the healthy weight range calculated?
It rearranges the BMI formula. Low weight equals 18.5 multiplied by your height in metres squared, and high weight equals 25 multiplied by your height in metres squared. In US units, weight in pounds equals BMI times height in inches squared, divided by 703.
Does the calculator work in US units?
Yes. You can enter your height in centimetres or in feet and inches. The result is shown in kilograms or pounds to match, using the standard BMI constant of 703 for the imperial conversion, and it updates live as you type.
Is BMI an accurate measure of healthy weight?
BMI is a useful, quick screening tool but it has limits. It uses only height and weight, so it can misclassify very muscular people as overweight and doesn't measure body fat directly. Pair it with body-fat or waist measurements for a fuller picture.
What should I do if my weight is outside the healthy range?
A number slightly outside the range isn't automatically a problem, since BMI ignores muscle, frame, and age. Use it as a prompt rather than a verdict. If you're concerned about being under or over the range, speak with a doctor or dietitian for individual guidance.