Calculate your ideal weight based on height. Uses the Hamwi formula for healthy body weight.
What is a Healthy Weight?
A healthy weight is one that minimizes the risk of weight-related diseases and allows for an active, full life. BMI (body mass index) is a commonly used tool to assess whether weight is in a healthy range, but it does not account for all factors such as muscle mass or fat distribution.
Factors Affecting Ideal Weight
Many factors influence healthy body weight: genetics, age, gender, physical activity level, and lifestyle. With age, muscle mass naturally decreases, which can affect weight. Women typically have a higher percentage of body fat than men at the same BMI. Therefore, it is worth treating the calculator as a starting point, not the final answer.
Body Composition – More Than Just Weight
Two people with the same weight can have completely different body composition. A person with high muscle mass may have a higher BMI but be in excellent shape. Visceral fat (stored around organs) is more dangerous than subcutaneous fat. Consider body composition testing (e.g., underwater weighing or bioelectrical impedance analysis) for a more complete picture.
Healthy Approach to Weight
Instead of chasing a specific number on the scale, focus on healthy habits: regular physical activity, balanced diet, and good sleep. Sudden diets and drastic restrictions can be harmful. Consulting a dietitian or doctor will help you set realistic and safe weight goals tailored to your individual situation.
Four formulas, four different answers
There is no single agreed ideal weight. The four formulas in common use were built decades ago for drug dosing and insurance tables, not for individual health advice, and they disagree with each other by several kilograms.
How it works
- Applies the Devine, Robinson, Miller and Hamwi formulas, all of which take a base weight at five feet and add a fixed amount per inch above it.
- Shows the healthy BMI range for the same height as a comparison.
- Adjusts the base figure for sex, which is how all four were originally specified.
each formula = base + increment × (inches over 60)
base (male) per inch
Devine 50.0 kg 2.30
Robinson 52.0 kg 1.90
Miller 56.2 kg 1.41
Hamwi 48.0 kg 2.70
BMI range = 18.5 to 25 × height² (metres)Worked example
A man of 178 cm, which is 70.08 inches, or 10.08 inches above five feet.
- Devine: 50 + 2.30 × 10.08 = 73.2 kg
- Robinson: 52 + 1.90 × 10.08 = 71.1 kg
- Miller: 56.2 + 1.41 × 10.08 = 70.4 kg
- Hamwi: 48 + 2.70 × 10.08 = 75.2 kg
- healthy BMI range: 58.6 to 79.2 kg
The four formulas span 70.4 to 75.2 kg — a 4.8 kg disagreement — and all four sit comfortably inside a BMI range 20.6 kg wide. That spread is the most useful thing here: it shows the precision these numbers appear to have is not real.
Reading the result
- These formulas were designed for clinical dosing, not for personal targets. Devine in particular was published in 1974 to calculate drug doses, and its use as a lifestyle benchmark came later and without evidence behind it.
- None of them account for body composition. A muscular person will exceed every one of these figures while carrying very little fat, which is the same limitation BMI has and for the same reason.
- The increment per inch differs by nearly double between Hamwi and Miller, which is why they diverge more the further you are from five feet. At very tall or very short heights they disagree substantially.
- Waist circumference and waist-to-height ratio predict health outcomes better than any weight-for-height formula. A waist under half your height is a more useful target than any of the four numbers above.
Common questions
- Which formula should I use?
- None of them alone. Their disagreement is the finding — anything inside the range they collectively describe, and inside a healthy BMI band, is unremarkable. If you want a single actionable number, measure your waist instead.
- Why do they differ for men and women?
- All four were specified with a lower base weight for women, typically by 4 to 5 kg, reflecting average differences in frame and body composition in the populations they were derived from. The per-inch increment is usually the same for both.