What is your ideal weight? MD Thordis Berger helps us do the math on the most common calculators.

The ideal weight – the subject of Ideal Body Weight remains a hot topic issue because it touches as well as aspects of human health and treatment. Along with the increased risk of type 2 diabetesheart attack, stroke and osteoarthritis, being overweight also increases the risk of getting several cancers.  For several treatments, a doctor has to know your weight to calculate the appropriate dosage. Besides, more people have become aware of health and fitness and want to have facts about their bodies, effectiveness of fitness training and efforts towards good health.

The origin of Ideal Body Weight

The first person to focus on the Ideal Body Weight (IBW) was Paul Broca (a French Army doctor) who had to establish the IBW weight for soldiers. His discovered and published the called Broca Index* that it was applied for about a full century. In his index, Broca only used the height in centimeters, and then subtracted 100 to get the normal weight. Then, 10% of the normal weight was subtracted to get the IBW.

Subsequent formulas were built

But the Broca Index failed in some aspects that are important to IBW. For example, it does not consider the current weight, age, and environment among others.

However, most of the subsequent formulae repackaged the Broca Index with only a few additions.

Today, the most reliable method of getting the ideal body weight whether in clinical, educational, or field settings is the Body Mass index (BMI).

ideal weight

It is a calculation that divides people into one of four categories: People who are underweight, with a score of less than 18.5; normal weight, with a score between 18.5 and 24.9; overweight, with a score of 25 to 29.9; and obese, with a score of 30 or greater. Basing this calculation on height and weight alone, however, doesn’t take into account a person’s bone, muscle, or fat proportions. For example, a person with exceptional muscle tone and low fat (like an Athlete, Bodybuilder, etc.) is more likely to have a higher BMI compared to someone with higher fat and lower muscle tone — this happens because muscle is four times as dense as fat tissue.

Using complementary modes of measurement may give a more accurate and complete indication of health risk, for example:

Tape Measure

To be considered healthy, waist circumference should be less than half of your height. According to the Center of Disease Control and Prevention (CDC), excessive abdominal fat may put you at greater risk for developing type 2 diabetes, high blood pressure, and coronary heart disease. To measure, stand straight and place the tape measure around your mid-section just above your hip bones along the belly button. Relax, do not suck in your gut, and do not compress the tape tightly around the waist.

tape measure waist line

tape measure waist line

Bioelectrical Impedance Scale

This scale is equipped with electrodes under each foot, which shoot tiny electrical impulses up throughout the body, and measures how quickly those impulses return to the device. Lean tissue conducts electrical impulses faster than fatty tissue, allowing the device to measure fat composition by the speed of the impulses return. The faster the response time, the leaner the physique.



  • Pai MP, Paloucek FP, The origin of the “Ideal” body weight equations. Ann Pharmacol 2000; 34:1066-69
  • Stehman CR, Buckley RG, Dos Santos FL, et al, Bedside estimation of patient height for calculating ideal body weight in the emergency department. J Emerg Med 2011;41:97-101
  • Matsuzawa Y, Tokunaga K, Kotani K, Keno Y, Kobayashi T, Tarui S, Simple estimation of ideal body weight from body mass index with the lowest morbidity. Diabetes Res Clin Pract 1990;10(Suppl. 1):S159-64.
  • Bhumika, S., Kathrn, S. and Clarie, B. (2006). Comparison of Ideal Body Weight Equations and Published Height-Weight Tables With Body Mass Index Tables for Healthy Adults in the United States. Nutritional Diabetics 1(3)312-319
  • Green B, Duffull S. (2002). Caution when lean body weight is used as a size descriptor for obese subjects. Clin Pharmacol Ther. 72:743–4.


* Broca Index

Men: Ideal Body Weight (kg) = [Height (cm) – 100] – ([Height (cm) – 100] x 10%)

Women: Ideal Body Weight (kg) = [Height (cm) – 100] + ([Height (cm) – 100] x 15%)