Ideal Weight Calculator
FORMULA ESTIMATE RANGE
Devine Formula
73.0 kg
Robinson Formula
71.0 kg
Miller Formula
70.3 kg
Hamwi Formula
75.3 kg
What Is Ideal Body Weight?
Ideal body weight (IBW) is a formula-derived reference weight based mainly on height and historical sex-specific constants.
Despite the word "ideal," these equations do not directly measure your healthiest personal weight, body-fat level, muscle mass or fitness.
Many classic IBW formulas became established through clinical and drug-dosing contexts rather than research designed to identify one perfect lifestyle target for every individual.
IBW and lean body mass are different concepts. Ideal body weight formulas do not measure actual tissue distribution or muscle mass.
How It's Calculated
All four formulas start from a reference value around five feet of height, then apply a formula-specific amount for each inch above or below that reference height. Because the starting values and increments differ, the same person can receive several different IBW estimates. Why the formulas disagree: The formulas were developed from different historical rules or height-weight datasets. Their disagreement does not mean the calculator is broken. It shows that "ideal weight" is not one directly measured biological value. Historical IBW formulas can behave differently, especially toward the shorter and taller ends of the height range, so the result should remain a reference estimate.
Devine (M: 50 + 2.3×D kg, F: 45.5 + 2.3×D kg) | Robinson (M: 52 + 1.9×D kg, F: 49 + 1.7×D kg) | Miller (M: 56.2 + 1.41×D kg, F: 53.1 + 1.36×D kg) | Hamwi (M: 106 + 6×D lb, F: 100 + 5×D lb), where D = height in inches − 60.
- D = Height in inches − 60
- Devine (1974): Male 50.0 kg + 2.3 kg/in; Female 45.5 kg + 2.3 kg/in
- Robinson (1983): Male 52.0 kg + 1.9 kg/in; Female 49.0 kg + 1.7 kg/in
- Miller (1983): Male 56.2 kg + 1.41 kg/in; Female 53.1 kg + 1.36 kg/in
- Hamwi (1964): Male 106 lb + 6 lb/in; Female 100 lb + 5 lb/in (converted to kg)
Sources
- Universal equation for estimating ideal body weight and body weight at any BMI — American Journal of Clinical Nutrition 2016 (PMID 27030535, PMCID PMC4841935)
- The origin of the "ideal" body weight equations — Annals of Pharmacotherapy 2000 (PMID 10981254, DOI 10.1345/aph.19381)
- Determination of ideal body weight for drug dosage calculations — American Journal of Hospital Pharmacy 1983 (PMID 6869387)
What to Do With Your Result
Treat the formula range as reference context rather than an instruction to gain or lose weight.
The equations do not know your muscle mass, body-fat distribution, health history, training status or personal goals.
If you want a height-and-weight screening metric, use the BMI Calculator.
If you want a circumference-based body-composition estimate, use the Body Fat Percentage Calculator.
If you're asking "how much should I weigh?", IBW formulas can provide historical reference estimates, but they cannot determine one universally correct personal weight.
Need.fit can use your actual goals, training and progress instead of treating one historical formula as your entire fitness target.