Developing Ideal Body Weight Estimates
This calculator can help users estimate their ideal body weight (in pounds or kilograms) using seven different approaches developed by scientists. The calculator requires four inputs:
- The user’s biological sex, which is different than gender or other social constructs
- Whether the user wants to enter information using the US Customary or Metric System
- The user’s weight in pounds or kilograms
- The user’s height in inches or centimeters
Using this information, the calculator then provides the user with the following:
- Their ideal weight using an approach published by Courtney M Peterson and appearing in the National Library of Medicine
- Their deviation, or delta from the ideal weight
- Six additional estimates, based on research conducted by each of the scientists listed (more on this later)
- The average of these six additional estimates
What is Ideal Anyway?
This calculator in no way is meant to body shame anyone. In fact, the calculator provides seven different results for body weight, which could be argued is counter to the concept of ideal. For example, the default values for this tool could be interpreted as ideal ranges from a low of 134 pounds to a high of 154, which is a twenty-pound range. Each of the calculations used is based on scientific research, six of which rely on the height of the user, while the seventh uses Body Mass Index (BMI) as the basis for the calculation.
Body Mass Index Defined, Pros and Cons
Body Mass Index, or BMI, is a screening tool used to assess whether a person has a healthy body weight relative to their height. The calculation for BMI is as follows:
BMI = eight (in kilograms) / (height (in meters))²
The calculation estimates body fatness and is used to assign individuals into one of four weight status categories. For example, BMI values and their corresponding categories are as follows:
- Underweight: BMI less than 18.5
- Normal weight: BMI between 18.5 and 24.9
- Overweight: BMI between 25 and 29.9
- Obesity: BMI of 30 or higher
Keep in mind that BMI is used as a screening tool, since it does not measure actual body fat percentage and it may not be accurate for certain individuals (such as athletes). The pros of using BMI include:
- The calculation is simple, requiring only two variables, making it easy to determine and interpret
- The approach can be used on large populations because it is both quick and standardized
- BMI is a low-cost solution to screen for obesity
- While the tool is considered a screening method, it can help identify individuals at risk for conditions associated with excessive body weight
The cons of using BMI include:
- The calculation of BMI does not consider factors such as muscle mass and bone density. For this reason, individuals with higher-than-average muscle mass, such as athletes, will have higher BMI values even with lower percentages of body fat
- Age, race, and gender are not considered when calculating BMI. The categories for BMI were based on studies of Caucasian populations, which may not be representative of other races
- Relying solely on BMI can result in unnecessary psychological distress and distorted body images
Interpreting the Results of Our Calculator
The calculator provides the user with seven estimates of the user’s ideal body weight. Each of these calculations is based on scientific research published by the person as indicated in the following publications:
- Peterson Courtney M, Thomas Diana M, Blackburn George L, Heymsfield Steven B. Universal equation for estimating ideal body weight and body weight at any BMI. The American Journal of Clinical Nutrition, Volume 103, Issue 5, May 2016, Pages 1197-1203.
- Hammond KA. Dietary and clinical assessment. In: Mahan LK, Stump SE, editors. Krause’s food, nutrition, & diet therapy. 11th ed. Philadelphia: Saunders; 2000.
- Miller DR, Carlson JD, Lloyd BJ, Day BJ. Determining ideal body weight (and mass). Am J Hosp Pharm 1983; 40:1622–5.
- Robinson JD, Lupkiewicz SM, Palenik L, Lopez LM, Ariet M. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm 1983; 40:1016–9.
- Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974; 8:650–5.
- Hamwi GJ. Therapy: changing dietary concepts. New York: American Diabetes Association; 1964.
- Pai MP, Paloucek FP. The origin of the “ideal” body weight equations. Ann Pharmacother 2000; 34:1066–9.