Ideal Body Weight Calculator
Calculate your ideal body weight for your height using various formulas with this IBW calculator.
How to calculate your ideal body weight
Ideal body weight (IBW) is an estimate of your healthy weight based on height and gender. This value is the optimal weight for a given height that corresponds to fitness activity and nutrition status.
If you can maintain your ideal body weight, you’ll have a lower risk of chronic health issues. Obesity increases the likelihood of heart disease, hypertension, diabetes, and even certain forms of cancer.
Calculating what your IBW should be is one way to ensure you are maintaining a healthy weight.
Formulas for calculating your ideal body weight
There are several different formulas to estimate ideal body weight. These formulas were used to approximate drug metabolism. But they relate more to ideal body weight than actual total body weight.
Most of the formulas use population data and weight trends. These ideal body weight equations all share a general agreement among the different height-weight tables from which they were based.
Background on formulas
Each of the formulas in the calculator shows different data. Here is some context on each of them.
The Devine Formula
The first IBW equation was developed by Ben Devine in 1974 to estimate drug clearance in obese patients. It only uses height to determine ideal body weight. It was initially based on estimates of ideal body weight and not population data.
Ideal Body Weight [kg] = 50 + (2.3 × (height [in] – 60))
Ideal Body Weight [kg] = 45.5 + (2.3 × (height [in] – 60))
The Hamwi Formula
The Hamwi formula is similar to the Devine but uses body frame in predicting ideal body weight and assumes a medium-sized frame. You can adjust this by either increasing by 10% for those with a large body frame or decreasing it by 10% for those with a small body frame.
Ideal Body Weight [lbs] = 106 + (6 × (height [in] – 60))
Ideal Body Weight [lbs] = 100 + (5 × (height [in] – 60))
Once you calculate the ideal body weight using the above equation, you can then adjust it based on your frame size. It may seem subjective, but, one way to determine frame size is by using your wrist measurement.
Using a tape measure, you simply measure the circumference of your wrist. If the wrist measurement is seven inches, the body frame is medium. Above seven inches is a large body frame, while measurements below seven inches correspond to a small body frame.
In addition, for individuals that are less than 60 inches in height (5 feet), you need to subtract 5 pounds for each inch below 60.
Small frame (- 10%), Large frame (+ 10%)
For heights, less than 60″, subtract 5 lbs. for each inch below 60.
The Robinson Formula
The Robinson Formula uses 1959 Metropolitan Life Insurance Company height-weight tables and was created to better assess ideal body weight for drug dosing.
Ideal Body Weight [kg] = 52 + (1.9 × (height [in] – 60))
Ideal Body Weight [kg] = 49 + (1.7 × (height [in] – 60))
Using this formula, a 5’5″ female would have an IBW of 49 kg + (1.7 × 5) = 57.5 kg
To convert this to pounds, multiply by 2.2.
57.5 kg × 2.2 lbs/kg = 126.5 pounds
The Miller Formula
Similar to the Robinson Formula, the Miller equation was developed using 1983 Metropolitan Life Insurance Company height-weight tables.
Ideal Body Weight [kg] = 56.2 + (1.41 × (height [in] – 60))
Ideal Body Weight [kg] = 53.1 + (1.36 × (height [in] – 60))
The values are slightly different as this formula was based on more recent population data.
Using this formula, a 5’5″ female would have an IBW of 53.1 + (1.36 × 5) = 60 kg
To convert this to pounds, multiply by 2.2.
60 kg × 2.2 lbs/kg = 132 pounds
Healthy weight range using the ideal body weight calculators
One of the downsides of calculating ideal body weight is that it’s only based on your height and gender and doesn’t factor in other criteria, like lean body mass, genetics, fitness level, or age.
And, unlike your body mass index (BMI), there is no set “healthy range” for ideal body weight. Recent studies found that in practice, it might be more useful to use BMI ranges instead of IBW formulas for men and women. But, you can use a BMI chart together with ideal body weight calculations to zero in on your ideal body weight range.
These formulas give you a good starting point to estimate your ideal body weight to ensure that fall within a healthy range for your height. But this is just one tool when putting together a fitness and nutrition program to meet your health goals. It should be combined with other measures such as lean body mass and body fat percentage when computing your own healthy ideal body weight.