Broca Index Calculator

Calculate classic Broca reference weight from height and compare current weight against that historical benchmark.

ImperialMetric

Height

5 ft 9 in

Current Weight

180 lbs

108.4

% of Broca

Near Broca (High)

Slightly above Broca reference range.

Broca Weight

166 lbs

Current / Broca

108.4%

Current vs Broca

+13.9 lbs

BMI Context

26.6

7090100110120130170

<90%90-100%100-110%110-120%120-130%130%+

Near Broca (High)

Current Weight vs Broca Reference

Broca is a historical height-based reference formula. Interpret with modern BMI and body-composition tools.

RANGE	CATEGORY	WHAT IT USUALLY MEANS
0-90	Well Below Broca Current weight is far below the Broca reference.	Current weight is far below the Broca reference.
90-100	Near Broca (Low) Near the Broca reference and below or at target.	Near the Broca reference and below or at target.
100-110	Near Broca (High) Slightly above Broca reference range.	Slightly above Broca reference range.
110-120	Above Broca Above Broca reference with moderate divergence.	Above Broca reference with moderate divergence.
120-130	High Above Broca Substantially above Broca reference.	Substantially above Broca reference.
130+	Very High Above Broca Large divergence from Broca target; use with modern tools for context.	Large divergence from Broca target; use with modern tools for context.

Broca Formula

The classic Broca reference is:

Broca Weight (kg) = Height (cm) - 100

This formula is historical and simple. It does not account for frame size, age, sex differences, or body composition, so it should be treated as a rough benchmark only.

How To Use Broca Index Today

Use Broca as a quick historical reference, then validate with modern tools: the BMI Calculator, Ideal Weight Calculator, and Weight Loss Calculator.

For calorie planning linked to these targets, use the TDEE Calculator and Calorie Deficit Calculator.

If your goal is body-composition quality rather than scale-only targets, combine with the Body Fat Calculator and FFMI Calculator.

References

Review of ideal-body-weight formula history (includes Broca formula context):Variability in IBW Formulae (PMC)
CDC BMI category framework for modern screening context:CDC BMI Categories

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