What this calculator returns
IBW means ideal body weight. This page returns the adult clinical reference weight produced by the selected male or female Devine equation from height.
Clinical Ideal Body Weight (IBW) Calculator
Clinical body-weight calculation
Calculate adult Devine ideal body weight
Select the male or female Devine equation, then enter an adult height of at least 5 feet (152.4 cm).
Sex used by the Devine equation
The Devine equations use different base weights. Use the equation specified by the relevant clinical reference or protocol.
Height entry
cm
Enter 152.4 to 250 cm without the unit, such as 175.
Height limit for this calculator
The Devine equations use 5 feet as their reference point. This calculator does not calculate below 5 feet (152.4 cm); use the method specified by the applicable clinical protocol instead.
Selected equation explained
How the Male Devine equation works
Select male or female above to update this equation. The calculator remains first so the clinical reference weight can be obtained without reading the longer explanation.
Male Devine ideal body weight formula
In simple words
Convert height to inches, subtract 60 inches (5 feet), multiply the inches above 5 feet by 2.3 kg, then add 50 kg.
- IBW
- = ideal body weight returned by the Devine equation, in kilograms
- height
- = adult height in inches; centimetres are divided by 2.54 first
- 60
- = 60 inches, which equals 5 feet
- 2.3
- = kilograms added for each inch above 5 feet
Why the male and female Devine results differ
Both equations add 2.3 kg for each inch above 5 feet. The male equation starts from 50 kg and the female equation starts from 45.5 kg, so the same height produces results that differ by 4.5 kg.
Use the weight measure named by the protocol
This calculator returns Devine IBW only. It does not calculate adjusted body weight or ventilation predicted body weight, and it does not decide which body-weight measure a medicine requires.
Verify the selected Devine equation, height, required body-weight measure, and final calculation independently.
What it does not return
It does not calculate a healthy target weight, adjusted body weight, measured actual weight, or ventilation predicted body weight. Those are separate clinical or consumer calculations.
Clinical interpretation
A result such as 70.5 kg means only that the selected Devine equation returned 70.5 kg for the entered adult height. Use that number only when the medication reference or protocol specifically requires Devine IBW.
How is ideal body weight calculated?
Height in centimetres is divided by 2.54 to convert it to inches. For adults at least 5 feet tall, the equation subtracts 60 inches, multiplies the inches above 5 feet by 2.3 kg, and adds the selected base weight.
Male Devine ideal body weight formula
In simple words
Convert height to inches, subtract 60 inches (5 feet), multiply the inches above 5 feet by 2.3 kg, then add 50 kg.
- IBW
- = ideal body weight in kilograms
- height
- = height in inches; divide centimetres by 2.54 first
- 60
- = 60 inches, equal to 5 feet
Female Devine ideal body weight formula
In simple words
Convert height to inches, subtract 60 inches (5 feet), multiply the inches above 5 feet by 2.3 kg, then add 45.5 kg.
- IBW
- = ideal body weight in kilograms
- height
- = height in inches; divide centimetres by 2.54 first
- 60
- = 60 inches, equal to 5 feet
Both equations use 2.3 kg for each inch above 5 feet. The male base is 50 kg and the female base is 45.5 kg, so the same height produces results that differ by 4.5 kg. Other IBW equations use different constants and can return different estimates.
Devine formula worked examples
Male example: 175 cm
Height (inches) = height (cm) ÷ 2.54
Height = 175 ÷ 2.54 = 68.8976 inches
Inches above 5 feet = 68.8976 − 60 = 8.8976
IBW (kg) = 50 + 2.3 × [height (inches) − 60]
IBW = 50 + 2.3 × 8.8976
IBW = 50 + 20.4646
IBW = 70.4646 kg
Exact result: 70.4646 kg. Displayed to one decimal place: 70.5 kg.
Female example: 160 cm
Height (inches) = height (cm) ÷ 2.54
Height = 160 ÷ 2.54 = 62.9921 inches
Inches above 5 feet = 62.9921 − 60 = 2.9921
IBW (kg) = 45.5 + 2.3 × [height (inches) − 60]
IBW = 45.5 + 2.3 × 2.9921
IBW = 45.5 + 6.8819
IBW = 52.3819 kg
Exact result: 52.3819 kg. Displayed to one decimal place: 52.4 kg.
Common ideal body weight examplesShowHide
Male 170 cm
170 ÷ 2.54 = 66.93 in; 50 + 2.3×6.93
65.9 kg
Male 180 cm
180 ÷ 2.54 = 70.87 in; 50 + 2.3×10.87
75.0 kg
Female 155 cm
155 ÷ 2.54 = 61.02 in; 45.5 + 2.3×1.02
47.9 kg
Female 165 cm
165 ÷ 2.54 = 64.96 in; 45.5 + 2.3×4.96
56.9 kg
Which body-weight measure does this page calculate?
Devine IBW
This is the only body-weight measure calculated on this page. Use it when the clinical reference explicitly requires Devine ideal body weight.
Actual or adjusted weight
Actual weight is measured. Adjusted weight is a separate formula that uses actual weight and IBW. Neither is calculated here.
Ventilation PBW
Predicted body weight for ventilation is a separate protocol-specific calculation. Do not substitute Devine IBW automatically.
Practice questions with workingShowHide
Practice 1: Male, height 175 cm. What is Devine IBW to 1 decimal place?
Convert height: 175 ÷ 2.54 = 68.8976 inches
Inches above 5 feet: 68.8976 − 60 = 8.8976
IBW: 50 + 2.3 × 8.8976 = 70.4646
Displayed to 1 decimal place: 70.5 kg
Answer: 70.5 kg
Practice 2: Female, height 160 cm. What is Devine IBW to 1 decimal place?
Convert height: 160 ÷ 2.54 = 62.9921 inches
Inches above 5 feet: 62.9921 − 60 = 2.9921
IBW: 45.5 + 2.3 × 2.9921 = 52.3819
Displayed to 1 decimal place: 52.4 kg
Answer: 52.4 kg
Practice 3: Male, height 5 feet 10 inches. What is Devine IBW?
Total height: 5 feet 10 inches = 70 inches
Inches above 5 feet: 70 − 60 = 10
IBW: 50 + 2.3 × 10 = 73
Answer: 73 kg
Ideal body weight FAQShowHide
What does IBW mean, and what does the result represent?
IBW means ideal body weight. Here it is the adult reference weight returned by the selected Devine equation from height and sex.
- The result is reported in kilograms.
- It is not measured body weight, a healthy-weight target, or a direct body-composition measurement.
- Use it only when the medication reference or clinical protocol specifically requires Devine IBW.
A 175 cm male adult has a Devine IBW of about 70.5 kg.
Which ideal body weight formula does this calculator use?
It uses the adult male and female Devine equations: a base weight at 5 feet plus 2.3 kg for each inch above 5 feet.
- Male: 50 + 2.3 × (height in inches − 60).
- Female: 45.5 + 2.3 × (height in inches − 60).
- The male and female equations differ by their 5-foot base weight.
Male 5 ft 10 in: 50 + 2.3×10 = 73 kg.
Can I calculate Devine IBW using centimetres or feet and inches?
Yes. The calculator accepts either system and converts centimetres to inches using 1 inch = 2.54 cm before applying Devine.
- The measurement-system switch converts a valid entered height.
- The formula is then applied using the full, unrounded height conversion.
- The step-by-step working shows the conversion used.
175 cm ÷ 2.54 = 68.8976 inches before the Devine equation is applied.
Why can two IBW calculators give different results?
They may use a different equation or round height at a different stage.
- Devine, Robinson, Miller, and Hamwi are different equations and are not interchangeable.
- Rounding centimetres-to-inches before the final step can slightly change the result.
- Use the named method required by the relevant clinical reference.
Rounding 68.8976 inches to 69 inches before calculating changes the displayed result slightly.
When should ideal body weight be used for medication calculations?
Only when the medicine information, prescription, pharmacist, or local protocol specifies ideal body weight or the Devine method.
- Many medicines use actual body weight instead.
- Some medicine-specific protocols use adjusted body weight.
- This calculator does not select the correct body-weight measure for a medicine.
Do not replace a prescribed actual-weight calculation with IBW simply because IBW is available.
Why does this calculator stop below 5 feet (152.4 cm)?
The Devine equations use 5 feet as their reference point, and this clinical calculator does not extrapolate them below that height.
- Some clinical tools and protocols restrict Devine IBW to people at least 60 inches tall.
- Short-stature policies can differ between organisations and calculations.
- Use the method explicitly specified by the applicable protocol.
A height of 150 cm is below this calculator's supported Devine range.
Is Devine IBW the same as actual, adjusted, or predicted body weight?
No. These are separate body-weight measures and may use different inputs and equations.
- Actual body weight is measured on a scale.
- Adjusted body weight is a separate medicine-specific calculation that uses actual weight and IBW.
- Ventilation predicted body weight uses a protocol-specific PBW equation and is not calculated here.
A Devine IBW result should not be copied into a ventilation PBW field unless the protocol explicitly says to do so.
Can this adult Devine calculator be used for children?
No. It is an adult clinical IBW calculator and is not a paediatric growth or dosing tool.
- Children and adolescents require age- and growth-specific methods.
- Do not substitute adult Devine IBW for a paediatric dosing policy.
- Follow the prescription, product information, and local paediatric protocol.
A paediatric mg/kg order normally begins with the prescribed paediatric weight method, not adult Devine IBW.
Continue calculating
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Open calculatorReferences and sourcesShowHide
Formula and historical context
Pai MP, Paloucek FP — The origin of the ideal body weight equations
PubMedAnn Pharmacother (2000)
Historical review of common ideal body weight equations and their clinical origins.
Chichester & Holmes — Ideal body weight: a commentary
PMCClin Nutr ESPEN (2021)
Clinical commentary summarising commonly used IBW equations, including Devine.
eviQ Body Surface Area Calculator — IBW and adjusted-weight formulas
ClinicalCancer Institute NSW
Australian clinical calculator documenting Devine IBW and a lower-height calculation limit.
Important scope distinction
References are provided for education. Follow the medication reference, pharmacist guidance, and local clinical protocol.