Ideal Weight Calculator
Enter your height and sex to see an ideal body weight range from five established formulas (Devine, Robinson, Miller, Hamwi and Lorentz) alongside the healthy weight range that a normal BMI implies. Adjust for your frame size, set a target BMI, and enter your current weight to see exactly how far you sit from the range.
Formula
Worked example
A man 175 cm (1.75 m): healthy BMI range = 18.5 to 24.9 × 1.75² ≈ 56.7 to 76.3 kg. Devine = 50 + 2.3 × 8.9 ≈ 70.5 kg at a medium frame.
How the Formulas Work
The classic formulas, Devine, Robinson, Miller and Hamwi, share the same structure: a base weight assigned at exactly 5 feet, plus a fixed number of kilograms for every inch of height above that mark. The Devine formula, for example, assigns a base of 50 kg for men and 45.5 kg for women, then adds about 2.3 kg per inch over 5 feet. Robinson, Miller and Hamwi use slightly different base weights and per-inch increments, which is why they produce a spread rather than a single number. Lorentz takes a different path, working straight from centimetres with a separate adjustment for men and women. Because each formula was derived from a different population and clinical purpose, their outputs collectively form a reference range rather than one authoritative target.
The BMI Healthy Weight Range and Target BMI
Alongside the formula estimates, the calculator shows the weight range that corresponds to a healthy Body Mass Index of 18.5 to 24.9 for your exact height: weight equals BMI times height in metres squared, evaluated at both ends. This BMI band is the range most public health bodies, including the WHO and CDC, actually use to define a healthy weight, so it is often the most useful single output here. You can also set a target BMI (22 is a common mid-range default) to get the precise weight that would put you at that BMI, which is handy when you want one clear goal weight rather than a spread of formula values.
Frame Size, Current Weight and Units
Real skeletal frames vary, so the calculator can widen or narrow the formula estimates by frame size: a small frame trims the numbers by roughly 10 percent and a large frame adds about 10 percent, matching the common clinical convention. Frame size is usually judged from wrist circumference relative to height, so the reference table below gives the wrist thresholds. Enter your current weight (in kilograms or pounds, your choice) and the calculator reports how far above or below the BMI healthy range you sit, turning a list of numbers into a clear, personal answer. Every weight is shown in both kilograms and pounds, and height can be entered in centimetres or inches.
What Affects Your Healthy Weight
These formulas were developed primarily from data on adults of average skeletal frame and do not account for muscle mass, bone density or body fat distribution, all of which shift what a healthy weight looks like for a specific person. Athletes with substantial lean muscle mass commonly exceed the formula range while carrying very little body fat, while older adults may fall inside the range yet carry enough visceral fat to add metabolic risk. Body composition measures such as waist circumference, a body fat percentage or a DEXA scan provide a fuller picture than scale weight alone.
Limitations and Edge Cases
The Devine formula, the most widely cited of the set, was originally created to guide medication dosing in hospital settings, not to define a population weight goal. The height-based formulas apply only to adults over 5 feet tall, as the per-inch adjustments lose accuracy below that threshold and are not validated for children or adolescents; below 5 feet the calculator falls back to the BMI range, which still holds. People with very short or very tall stature, those who are pregnant and individuals with conditions that alter body composition should treat these estimates with extra caution and consult a qualified healthcare provider for personalised guidance. This calculator is provided for general information purposes only and does not constitute medical advice.
Ideal weight formulas and frame size
| Formula / frame | Men | Women |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg/in | 45.5 kg + 2.3 kg/in |
| Robinson (1983) | 52 kg + 1.9 kg/in | 49 kg + 1.7 kg/in |
| Miller (1983) | 56.2 kg + 1.41 kg/in | 53.1 kg + 1.36 kg/in |
| Hamwi (1964) | 48 kg + 2.7 kg/in | 45.5 kg + 2.2 kg/in |
| Lorentz | (cm-100) - (cm-150)/4 | (cm-100) - (cm-150)/2 |
| Small frame (wrist) | < 6.5 in | < 5.5 in |
| Large frame (wrist) | > 7.5 in | > 6.25 in |
Base weight at 5 ft plus a per-inch increment, by sex; the frame thresholds use wrist circumference.
Frequently asked questions
Which ideal weight formula is the most accurate?
No single formula is definitively most accurate because each was derived from a different reference population and clinical purpose. The Devine formula is the most widely used in clinical settings, particularly for drug dosing, but studies show the formulas produce similar results for people of average frame and moderate height. For most people the healthy BMI weight range (BMI 18.5 to 24.9) is the more meaningful output, and a body composition assessment is more informative than any height-only estimate.
What is my ideal weight for my height?
A healthy weight for your height is better understood as a range than a single number. The five formulas here (Devine, Robinson, Miller, Hamwi and Lorentz) each give a slightly different estimate from your height and sex, and the healthy BMI band gives the weight range for a normal BMI at your height. The spread between them reflects the natural variation in body build; a clinician can help interpret where you fall in the context of your overall health.
How does frame size change my ideal weight?
The ideal body weight formulas assume an average (medium) frame. People with a smaller skeletal frame carry less, so a common clinical adjustment trims the estimate by about 10 percent for a small frame and adds about 10 percent for a large frame. Frame size is usually estimated from wrist circumference relative to height. This calculator applies that adjustment to the formula estimates when you select small or large frame.
Is ideal body weight the same as BMI?
No. Ideal body weight formulas return an absolute weight target derived from height and sex, while BMI divides weight by height squared and sorts people into categories such as normal, overweight or obese. This calculator shows both: the formula estimates and the weight range that a healthy BMI of 18.5 to 24.9 implies for your height, plus an optional target-BMI weight. Both approaches ignore muscle mass and fat distribution, which limits their value at the extremes of body composition.