Ideal Body Weight Calculator

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Ideal Body Weight Calculator
Devine Formula (Standard)Robinson FormulaMiller FormulaHamwi Formula
MaleFemale
Your Ideal Body Weight:
— kg
(– lbs)
function calculateIBW(){var gender=document.getElementById('gender').value;var formula=document.getElementById('formula').value;var ft=parseFloat(document.getElementById('h_ft').value)||0;var inches=parseFloat(document.getElementById('h_in').value)||0;var showSteps=document.getElementById('steps').checked;var totalInches=(ft*12)+inches;var over5ft=totalInches-60;if(totalInches<60){over5ft=0;}var ibw=0;function getIBW(f,g,ov){var res=0;if(f==='devine'){res=(g==='male')?50+(2.3*ov):45.5+(2.3*ov);}else if(f==='robinson'){res=(g==='male')?52+(1.9*ov):49+(1.7*ov);}else if(f==='miller'){res=(g==='male')?56.2+(1.41*ov):53.1+(1.36*ov);}else if(f==='hamwi'){res=(g==='male')?48+(2.7*ov):45.5+(2.2*ov);}return res;}ibw=getIBW(formula,gender,over5ft);document.getElementById('resultValueKG').innerHTML=ibw.toFixed(1);document.getElementById('resultValueLB').innerHTML='('+(ibw*2.20462).toFixed(1)+' lbs)';if(showSteps){var details='Formula Comparisons:
';var formulas=['devine','robinson','miller','hamwi'];for(var i=0;i<formulas.length;i++){var val=getIBW(formulas[i],gender,over5ft);details+=formulas[i].charAt(0).toUpperCase()+formulas[i].slice(1)+': '+val.toFixed(1)+' kg ('+(val*2.20462).toFixed(1)+' lbs)
';}document.getElementById('stepDetails').innerHTML=details;document.getElementById('stepDetails').style.display='block';}else{document.getElementById('stepDetails').style.display='none';}}

How to Use the Ideal Body Weight Calculator

The ideal body weight calculator is a tool designed to provide an estimate of a healthy body weight based on your height, gender, and scientifically validated formulas. While "ideal" weight is subjective and depends on body composition, muscle mass, and bone density, these formulas offer a clinical baseline used by medical professionals to determine medication dosages and general health targets.

Gender
Physiological differences in muscle mass and bone structure mean that men and women have different baseline weights for the same height.
Height (Feet and Inches)
Most IBW formulas use 5 feet (60 inches) as the base height and add weight for every inch above that mark.
Calculation Method
Select from Devine, Robinson, Miller, or Hamwi formulas, each of which applies slightly different weight increments per inch.

How the IBW Formulas Work

The ideal body weight calculator utilizes four primary equations. All of them follow a similar structure: a base weight for the first 5 feet of height, plus a specific amount of weight for every additional inch.

Devine Formula (Male) = 50kg + 2.3kg × (Inches over 5ft)

  • Devine Formula: The most widely used clinical formula for calculating drug dosages.
  • Robinson Formula: Developed in 1983 as a modification of the Devine formula to improve accuracy.
  • Miller Formula: Often used in academic settings, this formula yields slightly lower results for men and higher for women.
  • Hamwi Formula: The oldest of the group, frequently used in nutrition and dietetics.

Calculation Example

Example: Calculating the ideal body weight for a male who is 5 feet 10 inches tall using the Devine Formula.

Step-by-step solution:

  1. Base Height = 5'0″ (60 inches)
  2. Actual Height = 5'10" (70 inches)
  3. Inches over base = 70 – 60 = 10 inches
  4. Base Weight (Male) = 50 kg
  5. Additional Weight = 10 inches × 2.3 kg/inch = 23 kg
  6. Total IBW = 50 kg + 23 kg = 73 kg (Approx. 160.9 lbs)

Common Questions

Is IBW the same as BMI?

No. Body Mass Index (BMI) measures your weight relative to your height to categorize you (Underweight, Normal, Overweight). IBW provides a specific target weight based on historical medical formulas. Both are tools, but neither accounts for muscle-to-fat ratios.

Which formula is the most accurate?

The Devine Formula is the industry standard for clinical medical settings. However, the Robinson and Miller formulas are often considered more modern refinements. For general fitness goals, any of the four provide a reasonable starting point.

What if I am under 5 feet tall?

Most standard formulas are designed for adults 5 feet or taller. For individuals shorter than 5 feet, medical professionals typically use the base weight minus the weight per inch, or look at pediatric growth charts and BMI-for-age calculators instead.

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