Ideal Weight Calculator — Four Formula Comparison by Height
Calculate ideal weight using multiple formulas including Devine, Robinson, Miller, and Hamwi methods.
Ideal Weight Calculator
Quick Answer
Using the Hamwi formula, ideal weight for a 5'8" (173 cm) man is approximately 160 lbs (72.7 kg). For a 5'5" (165 cm) woman, ideal weight is approximately 125 lbs (56.7 kg). These are starting points — healthy weight ranges based on BMI (18.5–24.9) and individual body composition are more clinically relevant than a single number.
How the Ideal Weight Calculator Works Step by Step
An ideal weight calculator estimates a target body weight based on height using one of several clinical formulas developed in the 1960s–70s for medical dosing and research purposes. The four most common formulas are Hamwi (most widely used in clinical settings), Devine (used in pharmacology for drug dosing), Robinson, and Miller. Each produces slightly different results — the range between them provides a practical "ideal weight window" rather than a single number.
The Hamwi formula: for men, 106 lbs for the first 5 feet of height, plus 6 lbs per inch above 5 feet. For women, 100 lbs for the first 5 feet, plus 5 lbs per inch above 5 feet. A 5'10" man: 106 + (10 × 6) = 166 lbs Hamwi ideal weight. Robinson formula gives 163 lbs. Devine gives 166 lbs. The BMI-based range (18.5–24.9) gives 129–174 lbs. The convergence of multiple methods around 160–170 lbs provides a reasonable target range.
Important caveat: these formulas were developed from population data and don't account for individual body composition, muscle mass, age, or ethnic variation. A muscular athlete might have an ideal weight well above the formula's output. An older adult with significant muscle loss might have a healthy-looking weight while carrying excess fat. The BMI-based healthy weight range (18.5–24.9 × height²) provides a more practical approach than a single formula target.
Understanding Each Ideal Weight Calculator Input Field
Each field in the Ideal Weight Calculator serves a specific purpose. Here's why each input matters and how to provide the most accurate values:
Height
The primary predictor of ideal weight in all formulas. Height is squared in the BMI-based approach, making taller individuals have much wider acceptable weight ranges.
Sex
Women's ideal weight formulas give lower targets due to differences in average body composition — women naturally carry a higher percentage of essential body fat than men at equivalent lean mass.
Frame Size (optional)
Small frame: subtract 10% from calculated IBW. Large frame: add 10%. Frame size adjusts for skeletal structure variation. Measure wrist circumference to estimate: women < 5.5 inches = small frame; 5.5–5.75 = medium; > 5.75 = large frame.
Ideal Weight Calculator Formula and Methodology Explained
The Ideal Weight Calculatoruses the following validated formula. Understanding the math helps you interpret results accurately and trust the calculations you're relying on.
How the Ideal Weight Calculator Formula Works
All ideal weight formulas were empirically derived from clinical datasets (primarily hospitalized patients) rather than general population studies. They provide a useful clinical baseline for medication dosing and initial assessment. For individual weight goals, the BMI-based healthy weight range is more appropriate as it provides a target range rather than a single point estimate, and accounts for greater body composition variation.
When to Use the Ideal Weight Calculator
- →As a starting point when setting a weight loss or gain goal
- →In clinical settings for medication dosing calculations and nutritional assessment
- →Comparing to BMI-based healthy weight range for a comprehensive target picture
- →When setting goal weight for a body composition program alongside body fat percentage targets
💡 Expert Tips for Using the Ideal Weight Calculator Accurately
Use ideal weight as a reference point, not a rigid target — body composition (muscle-to-fat ratio) is more important than matching any formula's number.
A healthier goal for most people: target a BMI of 20–23 (mid-range normal) rather than the absolute upper or lower ideal weight boundary.
For strength trainers, ideal weight formulas consistently underestimate appropriate body weight — use body fat percentage targets (15–20% for men, 22–28% for women) as a more meaningful goal.
If you're within 10–15 lbs of any formula's ideal weight and feel healthy, that level of precision rarely justifies additional restriction — focus on body composition and fitness metrics instead.
⚠️ Common Ideal Weight Calculator Mistakes to Avoid
- ✗Treating a single ideal weight number as a definitive target without considering individual body composition — two people at the same weight and height can have vastly different health profiles
- ✗Ignoring muscle mass — athletic individuals will consistently appear 'overweight' by formula standards despite excellent health markers
- ✗Pursuing formula ideal weights that are genuinely too low for individual body structure, leading to unsustainable restriction
- ✗Not accounting for age-related body composition shifts — a 60-year-old's healthy weight may be 5–10 lbs above their 30-year-old ideal weight formula output due to normal body composition changes
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