“How much should I weigh?” has a range for an answer, not a number. This gives the range your height corresponds to inside the healthy BMI band, marks its middle, and says how far a current weight sits from it.
Key terms
- Healthy BMI band — 18.5 to 24.9, the range the CDC publishes for adults.
- The range — that band converted back into weights for your height. It is the answer.
- Mid-range target — a BMI of 22, which a published comparison found lands midway among the classical ideal-weight formulae.
How it works
Weight for a height at a given BMI
weight = BMI × height in metres²
Run at 18.5 and 24.9 for the ends of the range and at 22 for its middle. Imperial figures convert with the exact international pound and inch.
Because height is squared, the range widens as people get taller: at 1.75 m it spans about 20 kg, at 1.85 m about 22 kg. Two people the same height can both be squarely healthy and differ by the weight of a small child.
Why this is not the Devine formula
Most ideal-weight calculators run on Devine, Robinson and Miller — three variants of “start at a base weight for five feet, add so much per inch”. Their coefficients could not be read from any retrievable source: the paper documenting where they came from is abstract-only, and the two NIH-hosted papers that discuss them describe the equations without printing the constants. They are the kind of numbers that are easy to recall and easy to recall slightly wrong, and a weight target with a wrong constant in it looks entirely plausible.
So this runs on the healthy BMI band instead, which is readable end to end. That is not a downgrade: the paper cited above reports that a BMI of 22 sits midway among the published formulae anyway, and Devine’s own origin paper notes the data behind it were never published.
What a target weight cannot know
It does not know how much of you is muscle. Muscle is denser than fat, so a well-trained body can read above the range with nothing wrong at all — the same limitation BMI has, inherited here because this is BMI read backwards. It does not know your frame, your age, or what your weight has done over the last ten years, all of which a clinician would weigh before naming a number. Treat the range as context for a conversation, not as a goal to hit.
How to use this calculator
- Enter your height. The range comes out on its own — the weight field is optional.
- Add your current weight to see which side of the range you are on and by how much.
- Read the range, not the middle. Being inside it is what the evidence is about; where inside it you land is not.
- If the distance is large, take it to a clinician rather than to an arithmetic plan — how fast to change weight is a medical question.
Frequently asked questions
Why is the answer a range and not one number?
Because there is no single weight a height requires. The healthy band spans about 20 kg at average adult heights, and everybody inside it is inside it. A calculator that hands back one number is presenting the middle of a range as if it were a requirement.
How is this different from the BMI calculator?
It is the same relationship read the other way. BMI takes a height and a weight and gives a category; this takes a height and gives the weights that land in the healthy category, plus the distance from where you are now.
I lift weights and I am above the range. Is that a problem?
Not necessarily, and this page cannot tell. Muscle weighs more than fat for the same space, so a muscular body reads heavy on any height-and-weight method. The body fat percentage calculator answers a closer question, and a clinician answers the real one.
What about children, or during pregnancy?
Neither. The healthy BMI band quoted here is the adult one. Children are assessed against growth charts for their age and sex, and weight in pregnancy is followed by a midwife or doctor rather than against a target.
Should I aim for the middle of the range?
There is no evidence that says so, and this page does not suggest it. The middle is shown because a single figure is what people come looking for, and it is better to show one clearly labelled as the middle of a range than to let someone treat one end as the target.
