Healthy weight guide
Healthy Weight Range for Your Height
Alongside your BMI, the BMI calculator shows an estimated healthy weight range for your height, in either metric or imperial units. This guide explains where that range comes from, walks through the calculation with worked examples, and covers the limitations worth keeping in mind before treating any single number inside it as a personal target.
How the range is estimated
Your estimated healthy weight range is built the same way as your BMI category: it takes the adult reference range of 18.5 to 24.9 and applies it to your height, then converts each boundary into a weight. Because BMI depends on height squared rather than height itself, the resulting range widens for taller people and narrows for shorter ones. For the full chart showing how BMI results are grouped, see the adult BMI categories guide; for the calculation BMI itself is based on, the BMI formula guide with metric and imperial examples walks through it step by step.
Lower reference weight = 18.5 × height in metres²
Upper reference weight = 24.9 × height in metres²
Worked examples
Example — metric
An adult who is 1.75 m tall has a height squared of 3.0625 m². Multiplying by 18.5 gives a lower boundary of about 56.7 kg; multiplying by 24.9 gives an upper boundary of about 76.3 kg. The estimated healthy weight range for this height is roughly 56.7 kg to 76.3 kg. This is an illustration of the calculation, not a target weight for any individual.
Example — imperial
For imperial units, the same reference range can be applied to height in inches using the constant 703. For an adult who is 5 ft 6 in tall (66 inches): 18.5 × 66² ÷ 703 ≈ 115 lb, and 24.9 × 66² ÷ 703 ≈ 154 lb. The estimated healthy weight range for this height is roughly 115 lb to 154 lb. Again, this is an example of the arithmetic, not advice for any specific person.
Understanding the lower and upper limits
The lower boundary is the weight at which BMI equals 18.5 for a given height — below it, the adult reference range is classified as underweight. The upper boundary is the weight at which BMI equals 24.9 — above it, the range moves into overweight. Everything between the two is treated as the healthy weight reference range for adults; it is a window, not a single correct figure.
Why this isn't a single ideal weight
It is tempting to read the midpoint of the range as a personal goal, but the range is deliberately wide because it has to work for every adult at that height, regardless of frame, muscle mass, or body composition. Two people who share the same height and the same weight can carry very different amounts of muscle and fat, and both can be healthy at different points inside — or even just outside — the range. Treat it as a reference window, not a finish line.
Limitations to keep in mind
- Muscle mass — muscular adults can weigh more than the range suggests while carrying very little body fat.
- Body composition — the range reflects total weight relative to height only, not the proportion of fat, muscle, or bone.
- Age — body composition shifts over time, so the same weight can represent different proportions of muscle and fat at different ages.
- Waist measurement — where weight is carried adds health context that a height-based range cannot capture.
- Pregnancy — pregnancy involves weight changes that this adult reference range is not designed to assess.
- People under 18 — children and teenagers are assessed with age- and sex-specific growth charts, not this adult range.
- Individual health history — personal and family health history add context that a height-based estimate cannot provide.
These limitations apply to BMI more broadly, too — the BMI limitations guide covers athletes, aging, and pregnancy in more depth.
What to consider next
Common questions about the healthy weight range
Is the middle of the range my ideal weight?
No. The midpoint is simply the centre of a wide reference band, not a personal goal. Where a healthy weight falls for you depends on factors this calculation does not measure, such as muscle mass and body composition.
Why is the healthy range so wide?
Because it has to describe every adult at a given height, and people vary enormously in frame size, muscle mass, and body composition. A narrower range would fit fewer people accurately.
Can a muscular person be outside the range and still be healthy?
Yes. Muscle is denser than fat, so a muscular adult can weigh more than the upper boundary suggests while carrying very little body fat. The range cannot distinguish muscle from fat.
Does this range apply to children or pregnancy?
No. It is calculated from the adult BMI reference range and applies from age 18. Children and teenagers are assessed with age- and sex-specific growth charts, and pregnancy requires a different kind of assessment.
This content is for adults 18 years and older and is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.
Ready to see your own range?
Calculate your BMI to see your estimated healthy weight range, then use this guide to put the numbers in context.
How this content is maintained
T9 BMI Check is an educational resource for adults. The healthy weight range shown by our calculator is a screening reference calculated from the adult BMI range, not a personalized medical recommendation. We research our content against trusted public-health sources, work to keep it factually accurate, and review it periodically. T9 BMI Check is an independent informational website and is not affiliated with or endorsed by the organizations cited. For guidance about your own health, please consult a qualified healthcare professional.
References
- World Health Organization — Obesity and overweight
- NHS — Calculate your BMI (adults)
- NHLBI — Calculate Your BMI
- MedlinePlus — Body mass index (BMI)
Prepared and maintained by T9 BMI Check
Last reviewed against the cited sources: July 17, 2026