Your healthy weight range, not one number
Most weight questions get asked backwards. Someone steps on the scale, then wonders what the number means. This page starts from the other end: tell it your height, and it hands back the whole window the World Health Organization's adult scale considers healthy, before you weigh in at all.
That window comes from turning the standard BMI formula around. Healthy BMI runs from 18.5 to 24.9, so multiplying each end by your height in metres squared gives a weight range instead of a single score:
At 175 cm that comes out to 56.7 kg to 76.3 kg, a span of nearly twenty kilograms. Run your own height through the calculator above and it prints the exact figures, marks your current weight on the scale if you add one, and lists the weight at five BMI points along the way so you can see precisely how many kilograms or pounds separate you from either edge. If you would rather start from a weight you already know and see what BMI that produces, the BMI Calculator runs the same formula the other direction.
Choosing a target inside the range
A twenty-kilogram window is not an invitation to pick a number at random. Three things narrow it down for you specifically: how much muscle you carry, the width of your skeleton, and the weight your body has held comfortably for years as an adult, as opposed to the lowest figure you once reached on a strict diet and could not sustain.
A rough way to place yourself: if you carry little muscle and a narrow frame, the lower third of your range is a reasonable aim. An average build sits comfortably in the middle third. A broader skeleton, or real muscle mass built through regular training, points towards the upper third, sometimes even a little past the top edge of the BMI range without that meaning anything has gone wrong. The waist-to-height check further down this page is the practical tie-breaker when muscle and frame make the BMI window hard to read on its own.
The Ideal Weight Calculator takes a different approach again: four named formulas, Devine, Robinson, Miller and Hamwi, each producing one specific figure rather than a range. Those formulas were built decades ago for hospital drug dosing and insurance tables, not for picking a personal target, so they are worth comparing against this range rather than trusting on their own.
Why the range is wide
The twenty-kilogram spread is not a design flaw in the BMI scale, it is an honest admission that one height does not map to one healthy weight. Bodies at the same height differ in frame size, in how much of that weight is muscle rather than fat, and in how body composition shifts with age: most adults lose some muscle and gain some fat through their forties, fifties and sixties even when the number on the scale barely moves, so the same weight can describe two different bodies twenty years apart.
Ethnicity moves the goalposts too, not just the width. UK guidance from NICE sets lower BMI action points, 23 for overweight and 27.5 for obesity, for adults of South Asian, Chinese, Black African and African-Caribbean family background, because health risk from excess weight rises at a lower BMI in these groups, largely through a tendency to store more fat around the organs at a given weight. If that applies to you, treat the top of the standard range shown above as generous rather than exact, and weigh the waist check below more heavily.
When the range misleads
Four groups get a genuinely poor read from this page, and it is worth naming them plainly rather than burying the caveat in small print.
- Athletes and anyone seriously muscular. Muscle weighs more than fat at the same size, so a rugby forward or a competitive lifter can sit well above this range while carrying very little body fat. Above-range here is not automatically a problem for that build; a waist measurement settles it faster than the scale does.
- Older adults. Muscle lost with age can hide fat gained in its place, so a weight that lands neatly inside the range can still describe a body with more fat mass than the same weight would have carried at thirty. Muscle-preserving strength work matters more here than chasing a number inside the window.
- Pregnant women. Healthy weight gain in pregnancy is expected and necessary, and this range does not apply to it at all. A midwife or GP will track weight against pregnancy-specific guidance instead.
- Children and teenagers. Under-18s are assessed on age-and-sex percentile charts because a healthy weight changes through childhood in a way flat BMI thresholds cannot capture.
The waist-to-height back-up
Switch on the waist field and the calculator adds a second, independent check: keep your waist under half your height. UK NICE guidance recommends this exact rule for adults with a BMI under 35, alongside BMI rather than instead of it, because two people at an identical weight and height can carry very different amounts of fat around the organs, and BMI on its own cannot see the difference.
A ratio under 0.5 signals lower central-fat risk regardless of where you sit in the weight range above. From 0.5 up to 0.6 signals raised risk worth acting on, and above 0.6 signals high risk worth raising with a doctor. Measure midway between the bottom of your ribs and the top of your hip bones, roughly level with the belly button, tape snug but not pulled tight, after breathing out normally.
Questions people ask
Why does my healthy weight range span nearly 20 kilograms?
Because one height genuinely maps to a range of healthy bodies, not one correct weight. Frame size, muscle mass and age all shift where a healthy weight sits for two people of identical height, so the range has to be wide enough to cover that real variation rather than pretending it does not exist.
Should I aim for the exact middle of my range?
Not necessarily. The midpoint is a sensible starting guess if you have no other information, but a muscular or broad-framed person can reasonably target the upper third, and a slighter frame the lower third. Use the middle as a default, not a rule.
My weight is inside the range but my waist-to-height ratio is high. Which should I trust?
The waist ratio, in that case. A healthy-range weight with a raised waist-to-height ratio usually means fat sitting around the organs rather than spread evenly, which BMI and a simple weight range cannot detect but the waist measurement can.
Does this range apply if I am pregnant?
No. Healthy weight gain in pregnancy is expected, and this calculator is not built for it. Follow the weight guidance your midwife or GP gives you instead, which accounts for the stage of pregnancy rather than a fixed adult range.
Why is my healthy weight range different from a friend of South Asian heritage at the same height?
UK NICE guidance sets lower BMI action points, 23 for overweight and 27.5 for obesity, for people of South Asian, Chinese, Black African and African-Caribbean family background, since health risk from excess weight rises at a lower BMI in these groups. The standard 18.5 to 24.9 range shown here is the general adult figure; treat its upper edge as generous rather than exact if that guidance applies to you.
I train seriously and sit above the range. Should I lose weight?
Not on this figure alone. Weight training adds muscle, which weighs more than fat at the same size, so a well-trained body routinely sits above this range while carrying little body fat. Check your waist-to-height ratio above; if it reads under 0.5, the range is almost certainly misjudging your build rather than flagging a real problem.
How is this different from the BMI Calculator?
The BMI Calculator starts from a weight you already have and tells you the single BMI score and category it produces. This page runs the same maths the other way: starting from height alone, it hands you the entire healthy weight window before you enter a weight at all, then marks where your own weight falls inside it if you choose to add one.
This range estimates a healthy adult bodyweight window from population BMI data; it is not a medical assessment. Talk to a doctor about pregnancy, growth, or any weight that worries you outside of what this tool covers.