how to calculate lean body weight with a precise calculator
This single-column tool shows you how to calculate lean body weight quickly, confirms intermediate metrics, and provides a concise overview so you can understand how to calculate lean body weight before diving deeper.
Lean Body Weight Calculator
Enter your data to see how to calculate lean body weight instantly. Results refresh in real time so you learn how to calculate lean body weight with immediate feedback.
Male
Female
Used because formulas for how to calculate lean body weight differ by sex.
Key input for how to calculate lean body weight; must be realistic.
Height is required to complete how to calculate lean body weight accurately.
Optional but strengthens how to calculate lean body weight by showing fat mass.
Lean Body Weight (Boer Formula)
— kg
Using Boer method to show how to calculate lean body weight with sex-specific coefficients.
Lean Body Weight (Hume Formula)— kg
Fat Mass Estimate— kg
Lean Mass from Fat %— kg
BMI—
Lean % of Total Weight— %
Formula summary: For males: LBW = 0.407 × weight + 0.267 × height − 19.2. For females: LBW = 0.252 × weight + 0.473 × height − 48.3. This is the practical core of how to calculate lean body weight.
Lean vs Fat Mass Chart
Boer Lean Body WeightLean Mass from Fat %
The chart updates automatically to visualize how to calculate lean body weight under two methods.
Reference Table: How to calculate lean body weight across profiles
Profile
Weight (kg)
Height (cm)
Sex
Boer LBW (kg)
Hume LBW (kg)
Performance Athlete
80
182
Male
61.6
60.4
Active Professional
68
168
Female
47.8
46.9
Body Recomposition
90
178
Male
65.9
64.8
What is how to calculate lean body weight?
Understanding how to calculate lean body weight is essential for athletes, clinicians, and anyone improving body composition. When you grasp how to calculate lean body weight, you separate muscle, bone, and organ mass from fat mass, allowing more precise training and dosing decisions. People who want actionable nutrition targets often ask how to calculate lean body weight because total weight can be misleading.
Many assume how to calculate lean body weight is just removing fat, but the process depends on validated formulas like Boer and Hume. Anyone starting a resistance program benefits from knowing how to calculate lean body weight, and patients on medication often rely on how to calculate lean body weight to set correct dosing. Misconceptions arise when people think how to calculate lean body weight requires expensive tools; in reality, knowing how to calculate lean body weight with height, weight, and sex is accurate enough for planning.
how to calculate lean body weight Formula and Mathematical Explanation
To master how to calculate lean body weight, start with the Boer equation for males: LBW = 0.407 × weight(kg) + 0.267 × height(cm) − 19.2. For females, how to calculate lean body weight uses LBW = 0.252 × weight + 0.473 × height − 48.3. These coefficients adjust how to calculate lean body weight so that height and weight contribute realistically.
The Hume formula provides a second perspective on how to calculate lean body weight: males use 0.32810 × weight + 0.33929 × height − 29.5336; females use 0.29569 × weight + 0.41813 × height − 43.2933. By comparing both, you see how to calculate lean body weight within a range that reflects hydration and frame size. Subtracting fat mass (weight × body fat %) is another path for how to calculate lean body weight when skinfold or bioimpedance data exist.
Variable guide for how to calculate lean body weight
Variable
Meaning
Unit
Typical Range
Weight
Total body mass used in how to calculate lean body weight
kg
45–140
Height
Stature impacting how to calculate lean body weight frame size
cm
140–200
Sex
Biological sex altering coefficients in how to calculate lean body weight
–
Male/Female
Body Fat %
Proportion of fat to refine how to calculate lean body weight
%
8–40
Practical Examples (Real-World Use Cases)
Example 1: A 75 kg, 178 cm male wants to know how to calculate lean body weight to set protein targets. Using Boer, how to calculate lean body weight gives LBW = 0.407×75 + 0.267×178 − 19.2 = 58.6 kg. With 16% body fat, fat mass is 12 kg, so how to calculate lean body weight from fat yields 63 kg. The difference shows hydration and formula nuance, guiding his intake.
Example 2: A 62 kg, 165 cm female asks how to calculate lean body weight before chemotherapy dosing. Boer shows how to calculate lean body weight: 0.252×62 + 0.473×165 − 48.3 = 45.9 kg. Her 24% body fat means 14.9 kg fat, so lean mass is 47.1 kg. By comparing, clinicians validate how to calculate lean body weight and choose the safer figure.
Both examples repeat how to calculate lean body weight to demonstrate consistency across methods and to build intuition about how to calculate lean body weight for training or clinical care.
How to Use This how to calculate lean body weight Calculator
Follow these steps to apply how to calculate lean body weight correctly: enter sex, weight, height, and optional body fat. The calculator instantly performs how to calculate lean body weight via Boer and Hume, plus a body-fat-based estimate. Watch the chart update so you visualize how to calculate lean body weight across methods.
Read the main highlighted figure to see how to calculate lean body weight with Boer. Intermediate rows show Hume, fat mass, BMI, and lean percentage so you understand how to calculate lean body weight holistically. Use the copy button to share how to calculate lean body weight outputs with coaches or clinicians.
Key Factors That Affect how to calculate lean body weight Results
Several factors influence how to calculate lean body weight: hydration shifts; weight measurement error; height rounding; sex-specific coefficients; body fat estimation quality; and recent training sessions. When you explore how to calculate lean body weight, remember that glycogen depletion or sodium loading can swing results. Medical dosing that depends on how to calculate lean body weight must account for renal function and drug distribution volumes.
Financially, people using how to calculate lean body weight for nutrition purchases or coaching packages should budget for reassessment, since changes in training frequency alter how to calculate lean body weight over time. Insurance plans that reimburse wellness visits may also depend on how to calculate lean body weight to justify programs.
Frequently Asked Questions (FAQ)
Is how to calculate lean body weight the same as fat-free mass? They are closely aligned, so how to calculate lean body weight effectively tracks fat-free mass.
Which formula best shows how to calculate lean body weight? Boer is common clinically, while Hume offers a cross-check, both answering how to calculate lean body weight.
Do I need body fat data to learn how to calculate lean body weight? No, but adding body fat refines how to calculate lean body weight.
How often should I redo how to calculate lean body weight? Every 4–6 weeks during training blocks keeps how to calculate lean body weight aligned with progress.
Can dehydration change how to calculate lean body weight? Yes, fluid shifts can skew how to calculate lean body weight by a kilo or more.
Is how to calculate lean body weight useful for dosing? Many drugs scale to lean mass, so clinicians rely on how to calculate lean body weight.
Does age matter when learning how to calculate lean body weight? Age affects body composition, so rechecking how to calculate lean body weight is wise.
What if my numbers seem off when I try how to calculate lean body weight? Re-measure weight and height, then rerun how to calculate lean body weight in this calculator.
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var chartCtx = document.getElementById("lbwChart").getContext("2d");
var chartData = {boer:0,fat:0};
function validateInput(value,min,max){
if(value===""||value===null){return "Required for how to calculate lean body weight.";}
var num = parseFloat(value);
if(isNaN(num)){return "Enter a valid number to continue how to calculate lean body weight.";}
if(nummax){return "Value is too high for how to calculate lean body weight.";}
if(typeof min!=="undefined" && num<min){return "Value is too low for how to calculate lean body weight.";}
return "";
}
function calculateLBW(){
var gender = document.getElementById("genderSelect").value;
var weight = document.getElementById("weightKg").value;
var height = document.getElementById("heightCm").value;
var bf = document.getElementById("bodyFatPercent").value;
document.getElementById("genderError").innerText = "";
document.getElementById("weightError").innerText = "";
document.getElementById("heightError").innerText = "";
document.getElementById("bfError").innerText = "";
var errWeight = validateInput(weight,1);
var errHeight = validateInput(height,50);
var errBf = validateInput(bf,2,60);
if(errWeight!==""){document.getElementById("weightError").innerText = errWeight;}
if(errHeight!==""){document.getElementById("heightError").innerText = errHeight;}
if(errBf!==""){document.getElementById("bfError").innerText = errBf;}
var weightNum = parseFloat(weight);
var heightNum = parseFloat(height);
var bfNum = parseFloat(bf);
if(isNaN(weightNum)||isNaN(heightNum)||isNaN(bfNum)||errWeight!==""||errHeight!==""||errBf!==""){return;}
var boerLBW = 0;
var humeLBW = 0;
if(gender==="male"){
boerLBW = 0.407*weightNum + 0.267*heightNum – 19.2;
humeLBW = 0.32810*weightNum + 0.33929*heightNum – 29.5336;
}else{
boerLBW = 0.252*weightNum + 0.473*heightNum – 48.3;
humeLBW = 0.29569*weightNum + 0.41813*heightNum – 43.2933;
}
var fatMass = weightNum * (bfNum/100);
var leanFromFat = weightNum – fatMass;
var bmi = weightNum / Math.pow(heightNum/100,2);
var leanPercent = (boerLBW/weightNum)*100;
boerLBW = Math.max(0,boerLBW);
humeLBW = Math.max(0,humeLBW);
document.getElementById("mainLBW").innerText = boerLBW.toFixed(1) + " kg";
document.getElementById("humeLBW").innerText = humeLBW.toFixed(1) + " kg";
document.getElementById("fatMass").innerText = fatMass.toFixed(1) + " kg";
document.getElementById("leanFromFat").innerText = leanFromFat.toFixed(1) + " kg";
document.getElementById("bmiValue").innerText = bmi.toFixed(1);
document.getElementById("leanPercent").innerText = leanPercent.toFixed(1) + " %";
chartData.boer = boerLBW;
chartData.fat = leanFromFat;
drawChart();
}
function drawChart(){
var ctx = chartCtx;
ctx.clearRect(0,0,720,320);
var labels = ["Lean Weight"];
var series1 = [chartData.boer];
var series2 = [chartData.fat];
var maxVal = Math.max(series1[0],series2[0],1);
var padding = 60;
var barWidth = 120;
var gap = 40;
var xStart = (720 – (barWidth*2 + gap))/2;
// axes
ctx.strokeStyle = "#c7d1db";
ctx.lineWidth = 1;
ctx.beginPath();
ctx.moveTo(60,20);
ctx.lineTo(60,280);
ctx.lineTo(700,280);
ctx.stroke();
var ySteps = 5;
for(var i=0;i<=ySteps;i++){
var y = 280 – (240*(i/ySteps));
ctx.beginPath();
ctx.moveTo(55,y);
ctx.lineTo(700,y);
ctx.strokeStyle="#eef1f4";
ctx.stroke();
ctx.fillStyle="#5f7183";
ctx.font="12px Arial";
var labelVal = (maxVal*(i/ySteps)).toFixed(0);
ctx.fillText(labelVal+" kg",10,y+4);
}
// bars
var scale = 240/maxVal;
var boerHeight = series1[0]*scale;
var fatHeight = series2[0]*scale;
ctx.fillStyle="#004a99";
ctx.fillRect(xStart,280-boerHeight,barWidth,boerHeight);
ctx.fillStyle="#28a745";
ctx.fillRect(xStart+barWidth+gap,280-fatHeight,barWidth,fatHeight);
ctx.fillStyle="#0a2540";
ctx.font="14px Arial";
ctx.textAlign="center";
ctx.fillText("Boer LBW",xStart+barWidth/2,300);
ctx.fillText("Lean from Fat",xStart+barWidth+gap+barWidth/2,300);
ctx.fillText("Comparison of how to calculate lean body weight outputs",360,14);
}
function resetForm(){
document.getElementById("genderSelect").value = "male";
document.getElementById("weightKg").value = "72";
document.getElementById("heightCm").value = "175";
document.getElementById("bodyFatPercent").value = "18";
calculateLBW();
}
function copyResults(){
var text = "Lean Body Weight (Boer): "+document.getElementById("mainLBW").innerText+
"\nLean Body Weight (Hume): "+document.getElementById("humeLBW").innerText+
"\nFat Mass: "+document.getElementById("fatMass").innerText+
"\nLean from Fat: "+document.getElementById("leanFromFat").innerText+
"\nBMI: "+document.getElementById("bmiValue").innerText+
"\nLean %: "+document.getElementById("leanPercent").innerText+
"\nAssumption: Using how to calculate lean body weight via Boer and Hume with provided inputs.";
if(navigator.clipboard && navigator.clipboard.writeText){
navigator.clipboard.writeText(text);
}else{
var temp = document.createElement("textarea");
temp.value = text;
document.body.appendChild(temp);
temp.select();
document.execCommand("copy");
document.body.removeChild(temp);
}
}
calculateLBW();