Why use this calculator
The phrase ideal weight promises more precision than any formula can deliver, which is exactly why it is worth seeing several answers side by side. The three classical equations were built for different purposes and disagree with each other by several kilograms at the same height, and the healthy BMI range is wider still.
Showing them together makes the honest point: there is no single correct weight for a given height, only a range within which most people are healthy. That is a far better starting point for setting a target than one number implying an accuracy nobody has, and it stops a formula from becoming a goal it was never built to be.
How to use it
- Select your sex and enter your height accurately, measured against a wall without shoes rather than recalled from memory.
- Adults lose height slowly from their thirties and remembered figures are often out by two or three centimetres.
- The formulas use height alone, so there is nothing else to enter, which is simultaneously their convenience and their central weakness.
- Read the healthy BMI range alongside the formula results: it is wider, more defensible, and a better basis for a target, particularly if your build sits away from average.
What each result means
- Average Ideal Weight
- The mean of the three formulas, which is the single figure most people want. Though the range around it matters more.
- Robinson Formula
- A 1983 revision of earlier equations, generally considered the most accurate of the three for typical builds.
- Miller Formula
- A 1983 equation that produces slightly lower figures, particularly at greater heights.
- Devine Formula
- Developed in 1974 for medication dosing rather than health assessment, which remains its main clinical use today.
- Healthy BMI Range
- The weight range placing you between a BMI of 18.5 and 24.9. Wider than the formulas and a more defensible target.
The formula
Three classical equations are applied, all working from inches over five feet. Robinson: 52 kg plus 1.9 kg per inch for men, 49 kg plus 1.7 kg per inch for women. Miller: 56.2 kg plus 1.41 kg per inch for men, 53.1 kg plus 1.36 kg per inch for women. Devine: 50 kg plus 2.3 kg per inch for men, 45.5 kg plus 2.3 kg per inch for women. The healthy weight range is derived from BMI instead, being the weight that places you at a BMI of 18.5 and at 24.9 for your measured height.
How this number is used in practice
These equations were not designed for the purpose most people use them for. The Devine formula was created in 1974 to calculate drug dosages, where a standardised weight for height was needed regardless of body composition, and it is still used that way in hospitals today.
None of the three considers frame size, muscle mass, age or body composition, which is why a muscular athlete and a sedentary person of identical height receive the same answer despite obviously different healthy weights.
The practical use is as a sanity check rather than a target. If your weight sits far outside both the formula figures and the healthy BMI range, that is worth a conversation with a clinician. If it sits within the range but you want to change composition, the formulas have nothing more to offer.
Body fat percentage, waist circumference and strength markers all say more about health than a weight for height ever can.
Worked examples
Male, 5 ft 10 in
Formulas cluster around 71 kg (157 lb), with a healthy BMI range of 58.5 to 78.7 kg (129 to 174 lb).
Female, 5 ft 5 in
Formulas fall near 57 kg (126 lb), with a healthy BMI range of about 50 to 67 kg.
Male, 6 ft 2 in
Formulas sit near 80 kg, though the healthy BMI range spans roughly 65 to 87 kg. Far wider than the formulas suggest.
When people use it
- Getting a rough weight target for your height
- Comparing several formulas rather than trusting one figure
- Understanding a weight-for-height figure used clinically
- Setting a realistic range instead of a single goal weight
- Checking whether your current weight is far outside typical bounds
Tips
- Use the healthy BMI range rather than the single average. It is wider and more defensible.
- Measure height against a wall without shoes; remembered heights are frequently out by several centimetres.
- None of these formulas accounts for muscle mass, so athletes will read low.
- Frame size matters and is not an input; a genuinely large-framed person sits higher in the range.
- Body fat percentage and waist circumference tell you more about health than weight for height.
- Treat any target as a range rather than a number. A 5 kg band is more realistic than a single figure.
What it assumes, and where it stops being accurate
- All three formulas use height alone and ignore frame size, age, muscle mass and body composition.
- The Devine formula was developed for medication dosing rather than health assessment.
- The equations were derived from populations that may not represent your ancestry or build.
- The healthy BMI range inherits every limitation of BMI itself, including its blindness to composition.
- None of these figures is appropriate for children, adolescents or pregnant people.
Terms used on this page
- Robinson formula
- A 1983 equation estimating body weight from height, generally the most accurate of the classical three.
- Devine formula
- A 1974 equation developed for medication dosing, still used clinically for that purpose.
- Frame size
- Skeletal build, which shifts a healthy weight range and is not an input to any of these formulas.
- Healthy BMI range
- The weight span corresponding to a BMI of 18.5 to 24.9 at your height.
Questions people ask
- Which ideal weight formula is most accurate?
- Robinson is generally regarded as the most accurate of the three for typical adult builds, with Miller running slightly lower and Devine higher. The differences are several kilograms at the same height, which tells you something useful in itself: none is precise enough to treat as a single correct answer.
- Why do the formulas disagree with each other?
- They were derived from different populations for different purposes across the 1970s and 1980s. Devine was built for drug dosing rather than health, while Robinson and Miller were later revisions aimed at better accuracy. Since all three use height alone, small differences in the constants produce visible differences in the answer.
- Should I aim for my ideal weight?
- Aim for the healthy range rather than a single figure. Bodies vary in frame size and muscle mass in ways these equations cannot see, so a specific number can be unrealistic or unnecessary. Health markers like blood pressure, fitness, waist circumference and strength matter more than hitting a particular weight.
- Do these formulas account for muscle?
- No, and that is their main limitation. Someone who trains regularly carries more lean mass and will exceed all three figures while being perfectly healthy. If you carry noticeable muscle, use body fat percentage and waist circumference instead. Weight for height is measuring the wrong thing for you.
- What if my weight is outside the healthy range?
- It is worth discussing with a clinician, particularly if it has changed quickly or you have other symptoms. The range is broad by design, so sitting outside it is a genuine signal. Though athletes with substantial muscle are a well-known exception that a weight-for-height figure cannot distinguish.
Use this with
Ideal Weight Calculator answers one part of the question. These pick up where it stops: BMI Calculator, Body Fat Percentage Calculator, BMR Calculator and Calorie Calculator.
Where these figures come from
This calculation is jurisdiction-neutral arithmetic. No country-specific rules are applied.
- World Health Organization: obesity and overweight. BMI categories and health risk
- NIH: assessing your weight and health risk. Waist circumference and risk thresholds
Ideal Weight Calculator produces an estimate for general information. It is not financial, tax, medical, legal or engineering advice. read the full disclaimer. Spotted a wrong number? Report it and it gets fixed. The form picks up this calculator and the inputs you used.