Ideal Weight Calculator
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Find your ideal weight range using 4 scientific formulas. Shows the healthy BMI range for your height.
Ideal Weight Range
Healthy BMI range (18.5–24.9) for your height
📐 Formula
BMI range: Weight = BMI × height(m)². Hamwi male: 48 kg + 2.7 kg per inch over 5 ft. Female: 45.5 kg + 2.2 kg per inch over 5 ft
How to Use the Ideal Weight Calculator
Enter your height
Input height in feet/inches or centimetres. Height is the primary driver of ideal weight formulas — most are linear functions based on how much weight per inch or centimetre above a base height.
Select your sex
Most ideal weight formulas use different equations for men and women, reflecting average differences in bone density, muscle mass, and body composition between sexes.
Compare results across formulas
The calculator shows results from multiple methods (Hamwi, Devine, Robinson, Miller, and BMI range). The spread between formulas indicates the normal variation — there is no single correct answer.
Use as a broad guideline only
Ideal weight is a population-level estimate, not an individual prescription. An athlete with high muscle mass and a person of the same height with average muscle mass have very different ideal weights despite identical height.
The Five Ideal Weight Formulas Compared
Different formulas were developed for different purposes — clinical dosing, military fitness, population research — and produce meaningfully different results, particularly for tall or short individuals:
- Hamwi (1964): Men: 48 kg for 5 ft + 2.7 kg per inch over 5 ft. Women: 45.5 kg + 2.2 kg per inch. Developed for clinical drug dosing. Tends to give lower weights.
- Devine (1974): Men: 50 kg + 2.3 kg per inch over 5 ft. Women: 45.5 kg + 2.3 kg per inch. Also developed for clinical use (kidney function drug dosing).
- Robinson (1983): Men: 52 kg + 1.9 kg per inch over 5 ft. Women: 49 kg + 1.7 kg per inch. Slightly higher than Devine.
- Miller (1983): Men: 56.2 kg + 1.41 kg per inch over 5 ft. Women: 53.1 kg + 1.36 kg per inch. Gives the highest estimates.
- BMI range (18.5–24.9): Weight = BMI × height². Gives a weight range rather than a single number — arguably the most useful for practical application.
Why Ideal Weight Is Less Useful Than Body Composition
All ideal weight formulas share the same fundamental limitation: they use only height (and sometimes sex) to estimate a healthy weight, ignoring body composition entirely. A 175cm person with 20% body fat and a 175cm person with 35% body fat have the same ideal weight result from every formula, despite very different health profiles. Body fat percentage, waist-to-height ratio (below 0.5 is generally healthy for most adults), and muscle mass are better individual health indicators than scale weight relative to any formula.
The BMI-based range is arguably the most practical: rather than a single target weight, it provides a 10–15 kg window reflecting the natural variability in healthy body composition. For a 170cm person, the healthy BMI weight range spans from 53.5 kg to 72 kg — a 18.5 kg range reflecting legitimate variation in healthy body types at the same height.
When Ideal Weight Matters Clinically
Ideal body weight (IBW) formulas remain important in clinical medicine for calculating medication doses (particularly anaesthetics, chemotherapy, and antibiotics), estimating lung function, and setting nutritional targets in critical care. In these contexts, Hamwi and Devine are the most commonly used formulas. For individuals setting personal health goals, the BMI-based weight range combined with a waist circumference below 94cm (men) or 80cm (women) provides a more complete picture than any single ideal weight figure.
Sources & Methodology
Calculations are based on the most current publicly available data from authoritative government and industry sources:
Frequently Asked Questions
No single formula applies to everyone. The BMI-based range (18.5–24.9 × height²) is widely used. Hamwi and Devine formulas are commonly used in clinical settings. Body composition matters more than any formula.
Yes. Men generally have higher muscle mass, so most formulas give men a higher ideal weight than women at the same height. The difference is typically 2–5 kg at the same height.
Ideal weight is a guideline, not a strict target. Factors like muscle mass, bone density, and age all affect what's healthy for you. Consult a doctor or registered dietitian for personalised advice.