Broca Formula Ideal Weight Calculator
How to use this page
- Fill in the fields in the form above — the result recomputes at once, with no page reload.
- Under the result you will find the interpretation scale, if the calculator has one: it says which range your value fell into.
- The formula we use is shown lower on this page — you can check the arithmetic yourself.
- To compute the same for another game or variant, change it in the select field — prices and pools update automatically.
What this page does not do: It does not point to numbers to play and does not predict a draw — every draw is independent of the previous ones.
Further reading
The Broca formula is one of the oldest ways to estimate ideal body weight. Paul Broca, a French surgeon proposed it in 1871 in an utterly simple form: subtract 100 from your height in centimeters and you get your ideal weight in kilograms. A later modification added an adjustment for sex — for men the result is multiplied by 0.9, for women by 0.85, since women on average have a smaller share of muscle mass and wider hips at the same height. Take a man measuring 180 cm the calculation looks like this: (180 − 100) × 0.9 = 72 kg.
The simplicity of the formula is also its biggest weakness. Only two pieces of information are needed for the calculation: height and sex. It doesn't account for age, bone structure, body proportions, or training level. A person with an athletic build will get an underestimated result, while a small-boned person will get an overestimated one. It also fails at extreme heights: for someone measuring 145 cm it gives an unrealistically low value, and for a two-meter-tall man — a clearly inflated one, because body mass doesn't increase linearly with height.
Where does its popularity come from? Because it allows you to get an approximate figure in a few seconds that can be compared with actual body weight. A discrepancy of up to a few kilograms is normal — the formula only has approximate accuracy. A discrepancy exceeding a dozen or so kilograms is a signal to check something more precise, such as BMI, WHtR, or a body composition measurement. In modern medicine the Broca formula has given way to the BMI index, and for extreme body weight values it's worth consulting the result with a doctor rather than relying on a nineteenth-century formula.
Frequently asked questions
What is the Broca formula?
In the basic version, ideal weight equals height in centimeters minus 100. In the version with a sex coefficient, the result is multiplied by 0.9 for men and by 0.85 for women. A woman 165 cm tall has an ideal weight of (165 − 100) × 0.85 = 55.3 kg.
Is the Broca formula more accurate than BMI?
No. The Broca formula dates back to 1871 and only accounts for height and sex, while BMI relates weight to the square of height, which better describes the relationship between these values. Broca overestimates ideal weight for very tall people and underestimates it for short people.
For whom doesn't the Broca formula work?
The formula gives unreliable results for people under 150 cm and over 195 cm tall, for children, pregnant women, and people who train with weights. It also shouldn't be used for people after amputations or with significant swelling.
See also
BMI Calculator
Calculate your BMI based on body weight and height. See which range you fall into, learn the WHO scale, and fi
Harris-Benedict BMR Calculator
Calculate your basal metabolic rate using the Harris-Benedict equation. Enter weight, height, age and gender t
Lorentz Ideal Body Weight Calculator
Calculate ideal body weight using the Lorentz formula based on height and sex. See how it differs from the Bro