Ideal Weight Calculator – Free IBW Tool
Your ideal body weight (IBW) is an estimate of the healthiest weight for your height, age and sex, and rather than a single number it falls within a range. This free Ideal Weight Calculator works out your IBW using the six most widely used formulas (Devine, Robinson, Miller, Hamwi, Broca and a BMI-based method) so you can compare them at a glance.
How to use the Ideal Weight Calculator
The Ideal Weight Calculator is a really easy-to-use tool to check the appropriate weight for the given height of a person. First choose the unit systems: metric is for kg & cm, US units is for feet, inches, and pounds. The only thing you have to do is set your gender and your height in the chosen unit system and then click on the Calculate button.
Example Ideal Weight Calculations: METRIC UNITS
Example Ideal Weight Calculations: US UNITS
How do you calculate your ideal body weight?
To calculate your ideal body weight, you can use the following formulas:
Hamwi formula (1964)1
- Men Wt (lb) = 106 + 6 × (Ht − 60 in)
- Women Wt (lb) = 100 + 5 × (Ht − 60 in)
Devine formula (1974)2
- Men Wt (kg) = 50.0 + 2.3 × (Ht − 60 in)
- Women Wt (kg) = 45.5 + 2.3 × (Ht − 60 in)
Robinson formula (1983)3
- Men Wt (kg) = 52 + 1.9 × (Ht − 60 in)
- Women Wt (kg) = 49 + 1.7 × (Ht − 60 in)
Miller formula (1983)4
- Men Wt (kg) = 56.2 + 1.41 × (Ht − 60 in)
- Women Wt (kg) = 53.1 + 1.36 × (Ht − 60 in)
Peterson formula (2016)5
- US Wt (lb) = 5 × BMI + (BMI ÷ 5) × (Ht − 60 in)
- Metric Wt (kg) = 2.2 × BMI + 3.5 × BMI × (Ht − 1.5 m)
BMI formula for calculating ideal weight based on height6
(For most adults, an ideal BMI is in the 18.5 to 24.9 range.)
- Ideal Weightmin = 18.5*(Ht)2
- Ideal Weightmax = 24.9*(Ht)2
Whate are the limitations of IBW calculation?
Like all simple calculations, the Ideal Body Weight Calculator has some important limitations. First, although IBW or desirable weight was originally defined as the weight associated with the greatest life expectancy at each height, there is no single ideal weight that applies universally to all comorbidities and mortality-specific causes, and there is no single ideal weight that is applicable across all demographic factors, including age and ethnicity.
Second, IBW equations predict a single target body weight, whereas most clinicians favor, and the empirical data support, a range of target body weights. Third, IBW equations underestimated body weight at shorter heights and overestimated body weights at taller heights. For these reasons, IBW equations have largely been replaced by BMI-index, and BMI ranges.
Frequently asked questions
How is ideal body weight calculated?
Ideal body weight is estimated from your height, with adjustments for sex, using formulas such as Devine or Robinson. The Devine formula for men is 50 kg plus 2.3 kg for every inch over 5 feet.
What is the most accurate ideal weight formula?
No formula is perfect, as none account for muscle mass or body composition. The Devine and Robinson formulas are the most widely used in medicine, so comparing several results gives the most realistic picture.
Is ideal weight the same as a healthy weight?
Not exactly. Ideal weight formulas give a single target figure, while a healthy weight is a range based on BMI. Use both together for a fuller view.
Does ideal weight depend on age?
Height and sex matter most in the classic formulas, but age affects muscle and fat distribution. Older adults often sit comfortably at the higher end of the healthy range.
Why do men and women have different ideal weights?
On average men have more muscle and a larger frame than women of the same height, so the formulas add a higher base weight for men.