Calculate your ideal body weight using four established clinical formulas — Devine, Robinson, Miller, and Hamwi. Compare methods and get personalized health insights.
Select your biological sex
Your current age (18+)
Your height measurement
Your current weight to compare with ideal estimates
Robinson, J.D. et al. (1983). Ideal body weight in the elderly. Journal of the American Geriatrics Society, 31(10), 598-602.
Miller, D.R. et al. (1983). Drug dosing in renal failure. Clinical Pharmacology & Therapeutics, 33(6), 774-782.
Hamwi, G.J. (1964). Therapy: Changing dietary concepts. In: Danowski TS (ed.), Diabetes Mellitus: Diagnosis and Treatment, Vol. 1, pp. 73-78.
⚠️ Medical Disclaimer: Ideal body weight formulas are estimates originally developed for drug dosing calculations. They do not account for muscle mass, bone density, body composition, or individual health conditions. Use these results as a reference only. For personalized health assessments, consult a qualified healthcare provider or registered dietitian.
Personalized Insights
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Understanding Ideal Body Weight
What is Ideal Body Weight?
Ideal Body Weight (IBW) is a clinical estimate of the optimal weight for an individual based primarily on height and gender. Originally developed in the 1960s–1980s, IBW formulas were created for drug dosing calculations (especially for medications with narrow therapeutic windows) and as a screening tool in clinical nutrition.
Unlike BMI, which provides a weight range, IBW formulas produce a single specific weight for a given height and gender. The four most widely used formulas — Devine, Robinson, Miller, and Hamwi — each use slightly different base weights and height adjustments, reflecting different clinical populations and eras.
The Four Main Formulas
Devine Formula (1974)
Male: IBW = 50.0 kg + 2.3 kg for each inch over 5 feet Female: IBW = 45.5 kg + 2.3 kg for each inch over 5 feet
Most commonly used in clinical practice, especially for drug dosing. Developed from a study on gentamicin therapy in a predominantly male population.
Robinson Formula (1983)
Male: IBW = 52.0 kg + 1.9 kg for each inch over 5 feet Female: IBW = 49.0 kg + 1.9 kg for each inch over 5 feet
Modified from Devine to better reflect modern population demographics. Often used in geriatric and general medicine settings.
Miller Formula (1983)
Male: IBW = 56.2 kg + 1.41 kg for each inch over 5 feet Female: IBW = 53.1 kg + 1.36 kg for each inch over 5 feet
Developed with a focus on drug dosing in renal failure patients. Uses a higher base weight and smaller per-inch increment.
Hamwi Formula (1964)
Male: IBW = 48.1 kg + 2.7 kg for each inch over 5 feet Female: IBW = 45.4 kg + 2.7 kg for each inch over 5 feet
One of the earliest IBW formulas, still referenced in some clinical guidelines. Based on a study of mortality and weight in a general population.
How to Interpret Your Results
The four formulas will typically produce slightly different results. This is expected — each formula was derived from different populations and clinical contexts:
Devine tends to give the lowest estimates for taller individuals.
Hamwi tends to give higher estimates for taller individuals.
Robinson and Miller fall in between, with Robinson being slightly higher than Devine.
Women consistently have lower IBW than men of the same height across all formulas.
Clinical Use: IBW is most commonly used in drug dosing (especially for medications like aminoglycosides, vancomycin, and chemotherapeutic agents) and in nutritional assessments for hospitalized patients.
Limitations of Ideal Body Weight
Does not account for muscle mass: Athletes and muscular individuals may have IBW above healthy ranges.
Ignores body composition: Two people with same height/gender can have very different fat-to-muscle ratios.
No age adjustment: IBW formulas do not account for age-related changes in body composition.
Not for children: IBW formulas are validated for adults only (18+).
Ethnic variations: Different ethnic groups may have different body compositions at the same height/weight.
When to Use IBW vs. BMI
Use IBW for: Clinical drug dosing, nutritional assessments in hospital settings, and as a reference point in medical evaluations.
Use BMI for: General population screening, public health assessments, and weight category classification (underweight, normal, overweight, obese).
Best practice: Use both metrics alongside body composition analysis, waist circumference, and overall health indicators.
💡 Clinical Note: The Devine formula is the most commonly used IBW formula in clinical practice, particularly for drug dosing. However, many institutions now use adjusted body weight (ABW) for obese patients: ABW = IBW + 0.4 × (Actual Weight − IBW). This accounts for the fact that adipose tissue has different drug distribution characteristics than lean mass.
References & Further Reading
Pai, M.P. & Paloucek, F.P. (2000). The origin of the "ideal" body weight equations. Annals of Pharmacotherapy, 34(9), 1066-1069.
Robinson, J.D. et al. (1983). Ideal body weight in the elderly. Journal of the American Geriatrics Society, 31(10), 598-602.
Miller, D.R. et al. (1983). Drug dosing in renal failure. Clinical Pharmacology & Therapeutics, 33(6), 774-782.
Hamwi, G.J. (1964). Therapy: Changing dietary concepts. In: Danowski TS (ed.), Diabetes Mellitus: Diagnosis and Treatment, Vol. 1, pp. 73-78.
Frequently Asked Questions
Ideal body weight (IBW) is primarily used in clinical settings for:
Drug dosing: Many medications (aminoglycosides, vancomycin, chemotherapeutics) are dosed based on IBW or adjusted body weight.
Nutritional assessment: Used to estimate nutritional needs in hospitalized patients.
Ventilator settings: Used to calculate tidal volumes for mechanical ventilation.
There is no single "most accurate" formula — each has strengths and limitations:
Devine is the most widely used in clinical practice and drug dosing.
Robinson is considered an update to Devine for modern populations.
Miller and Hamwi are less commonly used but still referenced.
For clinical drug dosing, Devine remains the gold standard in many institutions.
Not exactly. IBW is a clinical estimate used for drug dosing and medical calculations. A healthy weight is a broader concept based on WHO BMI guidelines (18.5–24.9) that accounts for a range rather than a single number. IBW may fall inside or outside the healthy BMI range depending on height and body composition. For most people, a healthy weight range is more appropriate for general wellness guidance.
IBW formulas do not account for muscle mass. If you are very muscular, your IBW may be lower than your actual healthy weight. In clinical settings, healthcare providers may use adjusted body weight or lean body mass calculations for muscular patients. For general health, BMI and body fat percentage are often more informative than IBW alone.
Traditional IBW formulas do not include age as a variable. However, aging is associated with changes in body composition: muscle mass decreases and fat mass increases, even if weight remains stable. Some newer equations have been developed to account for age, but the classic formulas (Devine, Robinson, Miller, Hamwi) are age-independent. For older adults, healthcare providers often consider BMI and functional status alongside IBW.
No. The classic IBW formulas (Devine, Robinson, Miller, Hamwi) are validated for adults only (age 18+). For children and adolescents, healthcare providers use growth charts (CDC or WHO) that account for age, gender, and height percentiles. These are more appropriate than IBW formulas, which do not account for the rapid growth and development that occurs during childhood.
Each formula was developed using different populations and clinical contexts:
Devine: Based on a gentamicin study in a predominantly male population.
Robinson: Modified Devine to better reflect general populations.
Miller: Derived from renal failure patients.
Hamwi: Based on mortality data from an earlier era.
The differences reflect these different origins. The range of values is often more informative than any single number.
To calculate IBW manually:
Measure your height in inches (e.g., 5'7" = 67 inches).
Subtract 60 inches (5 feet) to get "extra inches" (e.g., 67 − 60 = 7 inches).
Adjusted Body Weight (ABW) is used for drug dosing in obese patients. The formula is:
ABW = IBW + 0.4 × (Actual Weight − IBW)
This accounts for the fact that adipose tissue has different drug distribution characteristics than lean muscle mass. Many hospitals use ABW for medications like vancomycin and chemotherapeutics in patients with BMI ≥ 30.