What is ideal body weight?
Ideal body weight (IBW) estimates lean body size from height and gender — not from your bathroom scale. This ideal body weight calculator (also called an IBW calculator) answers what is my ideal body weight with the clinical Devine formula ideal body weight, shows ideal body weight in kg and ideal body weight in pounds, and can add an adjusted body weight calculator step when actual weight is entered.
Why calculate ideal body weight
Asking how to calculate ideal body weight matters most for ideal body weight for drug dosing, ideal body weight for creatinine clearance, and ideal body weight for ventilator tidal volume teaching — not for vanity weight goals. Hydrophilic drugs distribute mainly into lean tissue; dosing on total body weight in obesity can overshoot, while pure IBW can undershoot. That is why protocols often move to ideal body weight calculation for medication dosing with AdjBW when excess weight is large.
Pair this page with the creatinine clearance calculator (actual / ideal / adjusted weight basis), the BMI calculator for habitus context, and the body surface area calculator when oncology-style BSA dosing is needed.
How this ideal body weight calculator works
Sex + height → Devine IBW; optional actual weight → AdjBW.
Ideal weight for height (Devine examples)
Teaching anchors for adults — not a personal health target.
Ideal body weight formulas
The primary ideal body weight calculator formula here is Devine (1974), matching common bedside and MDCalc-style practice. Height is converted to inches; inches above 5 feet (60 in) scale the result.
Devine formula
- Hamwi formula ideal body weight: male 48 + 2.7 × (in − 60); female 45.5 + 2.2 × (in − 60) — often used in nutrition.
- Robinson formula ideal body weight: male 52 + 1.9 × (in − 60); female 49 + 1.7 × (in − 60).
- Miller (1983) is shown for comparison; it is less common alone at the bedside.
Results differ by a few kilograms across formulas because each was fit to different historical data. For ideal body weight calculator for men and ideal body weight calculator for women, sex changes the base constant — height alone is not enough.
Adjusted body weight
When you enter actual weight, this tool also acts as an adjusted body weight calculator:
Adjusted body weight
The 0.4 factor estimates partial drug distribution into excess adipose tissue. Some monographs use 0.3 or drug-specific rules — always verify. If actual weight ≤ IBW, dosing education usually stays on actual weight (AdjBW collapses to actual here).
Calculation example
Female, height 65 in (165.1 cm), actual weight 180 lb (81.6 kg) — the Example button loads this case.
- Devine IBW = 45.5 + 2.3 × (65 − 60) = 45.5 + 11.5 = 57.0 kg (≈ 125.7 lb).
- Ratio ABW ÷ IBW ≈ 81.6 ÷ 57.0 ≈ 1.43 (~43% above IBW).
- AdjBW = 57.0 + 0.4 × (81.6 − 57.0) = 57.0 + 9.9 = 66.9 kg.
That AdjBW is the weight many aminoglycoside and CrCl teaching cases would carry forward — not a claim that every drug uses 0.4.
IBW chart & range
An ideal body weight chart is simply IBW tabulated by height for each sex. There is no single universal ideal body weight range like BMI 18.5–24.9 — IBW is a point estimate. Use the calculator for exact values; the visual bars above show typical Devine anchors. For screening adiposity, use the BMI calculator instead of treating IBW as a wellness range.
| Height | Female IBW | Male IBW |
|---|---|---|
| 5′0″ (152 cm) | 45.5 kg / 100 lb | 50.0 kg / 110 lb |
| 5′4″ (163 cm) | 54.7 kg / 121 lb | 59.2 kg / 130 lb |
| 5′8″ (173 cm) | 63.9 kg / 141 lb | 68.4 kg / 151 lb |
| 6′0″ (183 cm) | 73.1 kg / 161 lb | 77.6 kg / 171 lb |
| 6′4″ (193 cm) | 82.3 kg / 181 lb | 86.8 kg / 191 lb |
Drug dosing, CrCl & ventilators
Ideal body weight vs actual body weight: IBW ignores fat mass; actual weight includes everything. For ideal body weight for drug dosing, choose the basis the label or protocol specifies. For ideal body weight for creatinine clearance, Winter-style teaching often uses actual below IBW, IBW in a modest excess band, and AdjBW when BMI is high or ABW/IBW exceeds ~1.3 — see the home CrCl calculator Auto weight mode.
Ideal body weight for ventilator tidal volume typically uses predicted/ideal body weight from height and sex so obese patients are not ventilated with oversized volumes based on total weight.
Ideal body weight for elderly: formulas do not age-adjust. Sarcopenia can make “ideal” look high relative to measured lean mass — combine IBW with clinical judgment, albumin, and functional status.
How to calculate ideal body weight
- Measure standing height; convert to inches if needed (cm ÷ 2.54).
- Pick the sex-specific Devine base (50 kg male / 45.5 kg female).
- Add 2.3 kg for each inch above 60 in (5 feet).
- Report ideal body weight in kg; multiply by 2.2046 for pounds if required.
- If dosing in obesity, compute AdjBW = IBW + 0.4 × (ABW − IBW).
Ideal body weight FAQ
What is ideal body weight (IBW)?
A height- and sex-based estimate of lean body size used in dosing and ventilation education — not a fitness goal or diagnosis.
What is the Devine formula for ideal body weight?
Male: 50 + 2.3 × (inches − 60). Female: 45.5 + 2.3 × (inches − 60). Results are in kilograms.
How do you calculate adjusted body weight?
AdjBW = IBW + 0.4 × (actual − IBW). Confirm the correction factor in the drug monograph — some use 0.3 or drug-specific rules.
Devine vs Hamwi vs Robinson — which should I use?
Devine is the usual default for medication dosing education. Hamwi appears more in dietetics. Robinson is a later regression alternative. This calculator shows all four for transparency.
When is IBW used for creatinine clearance?
When body habitus makes actual weight a poor proxy for lean mass. Many protocols switch to AdjBW in obesity. Use the CrCl tool on this site with the matching weight basis.
Is IBW used for ventilator tidal volume?
Yes — lung-protective strategies commonly set mL/kg from predicted/ideal body weight by height and sex, not total body weight.
Does age change ideal body weight for elderly adults?
Classic Devine, Hamwi and Robinson equations ignore age. Interpret carefully when frailty or low muscle mass is present.
Ideal body weight vs actual body weight — what’s the difference?
IBW estimates lean size from height and sex. Actual body weight is measured on a scale and includes fat mass. Dosing protocols pick which basis to use.
Can I get ideal body weight in kg and pounds?
Yes. This IBW calculator reports Devine results in kilograms and pounds side by side after you calculate.
Is there an ideal body weight calculator for men and women?
Yes — select Female or Male first. Sex changes the Devine base constant (45.5 kg vs 50 kg); height alone is not enough.
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User Reviews
4.9 / 5 from 3 recent users of this ideal body weight calculator
Devine IBW plus AdjBW on one screen is exactly what I need before aminoglycoside and CrCl checks. Unit swap is fast on phone.
Clear IBW in kg and lb for ARDSNet-style tidal volume teaching. Formula comparison helps students see Devine vs Hamwi.
Optional actual weight for adjusted body weight is labeled clearly. Good educational notes without overclaiming.
After IBW, continue with the creatinine clearance calculator, BMI calculator, body surface area calculator, and eGFR calculator.