Ideal Weight Calculator
Calculate your ideal body weight range using the Hamwi, Devine, and Miller formulas based on height and sex.
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The ideal weight calculator estimates a healthy target weight range for your height using three established clinical formulas — Hamwi, Devine, and the healthy BMI range. Enter your height and sex for results from all three methods at once, giving you a range rather than a single arbitrary number. Ideal body weight formulas were originally developed for clinical pharmacology — calculating medication dosages that depend on lean body mass rather than total weight. They were not designed as fitness targets, though they have since been adopted in that context. The healthy BMI range (18.5–24.9) provides a broader bracket that accounts for natural variation in body composition. These estimates are starting points for conversation with a healthcare professional, not personal targets to chase in isolation. Muscle mass, bone density, age, and ethnic background all affect what a healthy weight actually looks like for a specific individual. Two people of the same height and sex can have very different ideal weights based on their frame size and muscle development. Consult a doctor or dietitian before setting weight goals. This calculator is for informational purposes only.
How to Use the Ideal Weight Calculator
The Ideal Weight Calculator is designed to give you an accurate answer in seconds. Follow these steps:
- Step 1: Enter your height (cm) in the Height (cm) field. The valid range is 100 to 250. The default is 175 cm. Adjust this to match your specific situation.
- Step 2: Choose your sex from the Sex dropdown. Select the option that most accurately reflects your current situation — this value feeds directly into the calculation.
- Step 3: Click Calculate to see your results instantly. The output updates as soon as you submit.
No account or sign-up required. All calculations run locally in your browser — nothing is stored or transmitted to any server.
Example Calculation
Here is what the Ideal Weight Calculator produces with its default values. Change any input above to recalculate instantly for your own figures.
Inputs
- Height (cm)175 cm
- Sex48
Results
- Hamwi Formula72.0 kg
- Devine Formula68.5 kg
- Healthy BMI range (lower, 18.5)56.7 kg
- Healthy BMI range (upper, 24.9)76.3 kg
How It Works
Hamwi (men): 48 kg + 2.7 kg per inch over 5ft | BMI range: 18.5–24.9 × height²
Three formulas calculate ideal body weight from height, each developed for different clinical contexts: Hamwi Formula (1964) — originally for insulin dosing: Men: 48 kg + 2.7 kg per inch above 5 feet Women: 45.5 kg + 2.2 kg per inch above 5 feet Devine Formula (1974) — widely used in pharmacokinetics: Men: 50 kg + 2.3 kg per inch above 5 feet Women: 45.5 kg + 2.3 kg per inch above 5 feet Healthy BMI Range (WHO, 18.5–24.9): Lower bound = 18.5 × height² (m²) Upper bound = 24.9 × height² (m²) Example: 175 cm male (5'9"). Hamwi = 48 + 2.7 × 9 = 72.3 kg Devine = 50 + 2.3 × 9 = 70.7 kg Healthy BMI range = 56.6–76.5 kg The BMI range is the widest and most flexible of the three, reflecting natural variation in body composition. The Hamwi and Devine figures represent single-point estimates that fall within the healthy BMI band for most heights.
Frequently Asked Questions
What is the ideal weight for my height?
Ideal weight is a range, not a single number. For a 175 cm male, the healthy BMI range is approximately 57–77 kg. For a 165 cm female, it is roughly 50–68 kg. The Hamwi and Devine formulas give single-point estimates within this range. Individual factors like muscle mass, bone density, and frame size mean the right weight for you may be anywhere within or near this band.
How accurate are ideal weight formulas?
Ideal weight formulas were designed for drug dosing calculations, not fitness goals — they estimate lean body mass for a given height. They are reasonable approximations for average body types but do not account for high muscle mass (athletes register as "overweight") or low muscle mass (which can make someone appear "healthy" despite metabolic risk). Use them as a rough reference, not a clinical target.
What is the difference between ideal weight and healthy BMI?
Ideal weight formulas (Hamwi, Devine) give a single estimated value. The healthy BMI range (18.5–24.9) gives a bracket of weights, typically spanning 20+ kg for most heights. The BMI range is wider because it reflects the natural variability in healthy body compositions. For most people, the formula estimates fall near the middle of the BMI range.
Does ideal weight differ for men and women at the same height?
Yes — the formulas use different base values. Women typically have a lower ideal weight than men at the same height due to differences in average muscle mass, bone density, and body composition. The Hamwi formula starts at 45.5 kg for women and 48 kg for men at 5 feet, with the same increment per additional inch. The healthy BMI range is the same threshold for both sexes.
Is the ideal weight calculator free?
Yes — free with no sign-up needed. Enter height and sex for instant results across three clinical formulas. All calculations run in your browser and no data is stored. For personalised weight guidance, consult a healthcare professional.