🎯Ideal Body Weight Calculator

Ideal body weight — what is it and how to calculate it?

Ideal body weight is a reference value determined from height, sex, and a chosen empirical formula. Our calculator computes it simultaneously using three methods: the modified Broca formula, the Lorentz formula, and as the normal range derived from BMI (18.5–24.9). This lets you compare results and build a more complete picture. All calculations are performed in real time — enter your height and see the results instantly.

Differences between methods and when to use them

The Broca and Lorentz formulas were developed as simple clinical rules and work well for a quick assessment of a target weight. The normal BMI range is more flexible — instead of a single number it shows a from-to range, which better reflects natural human variability. Neither method accounts for body composition, however: a person with high muscle mass may exceed their `ideal weight` while being in excellent health. Treat the results as a reference point, not a goal in itself.

Frequently asked questions

What is ideal body weight?

Ideal body weight is an estimated weight considered optimal for a given height. It is determined using various empirical formulas — including Broca and Lorentz — or based on the normal BMI range (18.5–24.9). The result is an indicative value and does not account for body build or muscle mass.

How does the modified Broca formula work?

The modified Broca formula uses (height in cm − 100) as a starting point, then applies a sex-based correction: men 10% (result × 0.9), women 15% (result × 0.85). Example for a 180 cm man: (180 − 100) × 0.9 = 72 kg.

How does the Lorentz formula work?

The Lorentz formula for men is: (height − 100) − (height − 150) / 4; for women: (height − 100) − (height − 150) / 2. It gives slightly different values than Broca, taking body proportions into account. At heights close to 150 cm, both formulas converge to a similar result.

Do the calculator results replace medical advice?

No. The calculator provides indicative values based on statistical formulas. It does not account for individual body build, muscle mass, health status, or other factors. If you have concerns about your body weight, consult a doctor or dietitian.