65.2
kg
143.7
lb
66.9
in
6.9
in
58.6
kg
71.7
kg
65.2
kg
143.7
lb
66.9
in
6.9
in
58.6
kg
71.7
kg
The Robinson formula for ideal body weight was published in 1983 by James D. Robinson and colleagues in the American Journal of Hospital Pharmacy. It was developed as a data-driven alternative to the Devine formula, which had been derived more from clinical observation than statistical analysis. Robinson and his team used actuarial data from the Metropolitan Life Insurance Company's height-weight tables to create a formula that more closely matched the weights associated with the lowest mortality rates in large population studies.
The Robinson formula uses a slightly different approach than Devine. For males, the base weight is 52 kilograms (compared to Devine's 50 kg) with an increment of 1.9 kilograms per inch over 60 inches (compared to Devine's 2.3 kg). For females, the base is 49 kilograms (versus 45.5 kg) with a 1.7 kg increment (versus 2.3 kg). These differences result in the Robinson formula giving slightly higher weights for shorter individuals and slightly lower weights for taller individuals compared to the Devine formula, which may better reflect the non-linear relationship between height and optimal weight.
The use of Metropolitan Life Insurance data gives the Robinson formula a strong epidemiological foundation. The Met Life tables were based on mortality data from millions of policyholders and identified the weight ranges at each height associated with the greatest longevity. By deriving a linear regression formula from these data, Robinson created an equation that could reproduce these optimal weights without needing to reference the original tables. This approach gives the Robinson formula arguably better population-level validity than the Devine formula.
In modern clinical practice, the Robinson formula is used alongside other IBW formulas to provide a more comprehensive picture. Some institutions prefer Robinson over Devine for nutritional assessments because of its actuarial data basis, while Devine remains the standard for pharmacological dosing due to historical convention. The Robinson formula is particularly valued in research settings where investigators need to reference a formula grounded in mortality data rather than clinical observation alone.
This calculator implements the Robinson formula with automatic centimeter-to-inch conversion. Results are shown in both kilograms and pounds, with a plus/minus 10% range for frame size variation. Compare your results with those from our Devine, Miller, and Hamwi formula calculators, or use our comprehensive Ideal Weight Calculator to see all four formulas simultaneously. Understanding the range of estimates helps you identify a realistic and healthy weight target.
The Robinson formula (1983) calculates ideal body weight as: Males: IBW = 52 + 1.9 x (height in inches - 60) and Females: IBW = 49 + 1.7 x (height in inches - 60). Height in cm is converted to inches by dividing by 2.54. The lower per-inch increment compared to Devine (1.9 vs 2.3 for males) results in lower estimates for taller individuals and higher estimates for shorter individuals.
Robinson IBW tends to be slightly lower than Devine for tall individuals and slightly higher for short individuals. The result represents the weight associated with lowest mortality in insurance actuarial data. The 10% range provides a window for frame size variation. If your weight falls within this range, you are near the statistically optimal weight for longevity based on population data.
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Results
A 180 cm male has a Robinson IBW of 66.9 kg, notably lower than the Devine estimate of 75.0 kg for the same height.
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Results
A 165 cm female has a Robinson IBW of 52.3 kg, slightly lower than the Devine estimate of 57.0 kg.
The Robinson formula was developed by James D. Robinson, Sharon M. Lupkiewicz, and Lucy Wright, published in the American Journal of Hospital Pharmacy in 1983. They aimed to create a more statistically grounded IBW formula based on actuarial mortality data.
Robinson uses a higher base weight but lower per-inch increment than Devine. This means Robinson gives higher weights for shorter people and lower weights for taller people. Robinson was derived from mortality data while Devine was based on clinical observation.
The Robinson formula uses a smaller per-inch increment (1.9 vs 2.3 kg for males) because the actuarial data showed that the relationship between height and optimal weight is not as steep as Devine assumed. This may better reflect reality for very tall individuals.
Neither is definitively more accurate. Robinson has better statistical grounding in mortality data, while Devine is more established in clinical protocols. The truth likely lies in the range between the two, which is why using multiple formulas is recommended.
While Robinson can be used for drug dosing, most pharmacological guidelines specifically reference the Devine formula due to historical convention. Robinson is more commonly used in nutritional assessment and research settings.
Robinson used the 1983 Metropolitan Life Insurance Company height-weight tables, which were derived from mortality data of millions of insurance policyholders. These tables identified the weight ranges associated with the longest life expectancy at each height.
Like Devine, the Robinson formula does not directly account for frame size. The 10% range (shown in this calculator) is a common clinical adjustment to accommodate small and large frames. The original Met Life tables did include frame size categories.
Yes, you can compare Robinson IBW to your BMI-based healthy weight range. For most heights, Robinson IBW falls near a BMI of 21-22, which is in the middle of the normal BMI range (18.5-24.9).
The Robinson formula is validated for adults. The Met Life data included policyholders across adult age ranges but did not include children or adolescents. For pediatric populations, use age-specific growth charts.
Robinson provides a useful second opinion grounded in mortality data. When Robinson and Devine give similar results, you can be more confident in the estimate. When they diverge significantly, it suggests your height is at an extreme where formula selection matters more.
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