Calculate Wilks Score & Compare Strength Across Weight Classes
Kilograms (kg)
Pounds (lbs)
Select the unit used for bodyweight and lifted weight.
Male
Female
Coefficients differ significantly based on physiological differences.
Enter your current body weight.
Please enter a valid positive body weight.
The sum of your best Squat, Bench Press, and Deadlift (or single lift).
Please enter a valid positive weight.
Wilks Score
0.00
Calculated using the standard Wilks formula for powerlifting comparison.
Relative Strength0.00x(Lift / Bodyweight)
IPF Points (Approx)02019 Standard
Est. Classification–Standard Comparison
Strength Curve Visualization
This chart shows how your Wilks score (Blue Line) changes relative to body weight if your total lifted weight remains constant. The dashed line represents the average progression.
Comparison Table
Metric
Your Stats
Average (Int.)
Elite
Comparison based on general strength standards for your body weight class.
What is a Weight Lifting Coefficient Calculator?
A Weight Lifting Coefficient Calculator is an essential tool for powerlifters and strength athletes used to compare strength levels across different body weight categories. In sports like powerlifting and weightlifting, lighter athletes naturally lift less absolute weight than heavier athletes. However, pound-for-pound, lighter athletes are often stronger. A coefficient formula standardizes these differences to create a level playing field.
The most common formula used is the Wilks Coefficient, though others like Sinclair (for Olympic lifting), DOTS, and IPF Points exist. This calculator primarily uses the Wilks formula to generate a score that reflects your relative strength potential.
Weight Lifting Coefficient Formula and Mathematical Explanation
The calculation relies on a 5th-degree polynomial equation derived from statistical data of lifters across all weight classes. The goal is to produce a coefficient number that can be multiplied by the weight lifted to give a standardized score.
Where 'x' is the body weight of the lifter in kilograms.
Variable Definitions
Variable
Meaning
Unit
Typical Range
x
Body Weight
kg
40kg – 200kg+
Lifted Weight
Total of Squat + Bench + Deadlift
kg or lbs
100kg – 1000kg+
a – f
Polynomic Constants
constant
Specific to biological sex
Score
Standardized Strength Rating
Points
200 – 600+
Table 1: Variables used in the Wilks calculation logic.
Practical Examples (Real-World Use Cases)
Example 1: The "David vs. Goliath" Scenario
Imagine two lifters competing for the "Best Lifter" award at a local meet.
Lifter A (Lightweight): Male, 75 kg (165 lbs). Total lift: 500 kg.
Lifter B (Heavyweight): Male, 120 kg (264 lbs). Total lift: 650 kg.
Analysis: Lifter B lifted 150 kg more in absolute terms. However, using the Weight Lifting Coefficient Calculator:
Lifter A's Wilks Score: ~356.5
Lifter B's Wilks Score: ~372.8
Result: Lifter B wins, but the margin is much smaller (16 points) than the absolute weight difference suggests. The coefficient reveals that Lifter B's size advantage was utilized effectively.
Example 2: Tracking Personal Progress While Bulking
A female lifter decides to gain weight to increase strength.
Start: 60 kg body weight, 300 kg total. Score: ~334
End: 65 kg body weight, 320 kg total. Score: ~338
Analysis: Even though she gained body weight (which usually lowers the coefficient multiplier), her strength increased enough to offset the penalty. Her score went up, indicating true relative strength gains, not just mass leverage.
How to Use This Weight Lifting Coefficient Calculator
Select Unit: Choose between Kilograms (kg) or Pounds (lbs). The calculator automatically converts inputs for the formula.
Select Sex: Choose Male or Female. This is critical as the polynomial constants are derived separately for biological sexes.
Enter Body Weight: Input your weight on the day of the lift. Be precise (e.g., 82.5).
Enter Total Lifted: Input the sum of your best lifts (Squat + Bench + Deadlift).
Review Results:
Wilks Score: Your primary standardized score.
Relative Strength: How many times your body weight you lifted.
Class: A rough estimate of where you stand (Beginner to Elite).
Key Factors That Affect Weight Lifting Coefficient Results
Understanding what influences your score helps in strategic planning for competitions.
Body Composition: Muscle moves weight; fat does not. A lifter with higher body fat at the same weight as a leaner lifter will likely have a lower coefficient because they have less contractile tissue generating force per kilogram of body mass.
Sex Differences: Men and women have different centers of gravity and muscle mass distributions. The coefficients are mathematically distinct to allow fair comparison within sex categories, though comparing scores across sexes is debated.
Weight Cuts: Dropping water weight before weigh-in lowers 'x' (body weight) in the formula, artificially inflating the score if strength is maintained. This is a common strategy in competitive powerlifting.
Height and Levers: While the calculator uses weight, height plays a physics role. Taller lifters often have to move weights a greater distance (more work), potentially disadvantaging them in the strict "weight vs. weight" coefficient model compared to shorter, stockier lifters.
Training Age: Beginners often see rapid coefficient increases due to neurological adaptations, while advanced lifters fight for single-point increases.
Equipment (Gear): The formula assumes "Raw" or specific equipped standards. Wearing supportive suits (single-ply/multi-ply) adds absolute weight, inflating the score unless compared against other equipped lifters.
Frequently Asked Questions (FAQ)
What is a good Wilks score?
Generally, a score of 300 is considered respectable for an intermediate lifter. 350+ is advanced, 400+ is national level competitive, and 500+ is elite/world class.
Does this calculator work for single lifts?
Yes. You can enter your Bench Press max as the "Total Lifted" to get a coefficient specifically for that lift, often used in "Bench Only" competitions.
Why did my score go down when I got stronger?
If you gained body weight faster than you gained strength, your coefficient will drop. The formula penalizes increased body mass to ensure fair comparison.
Is Wilks better than Sinclair?
They serve different sports. Wilks is the standard for Powerlifting (Squat/Bench/Deadlift). Sinclair is the standard for Olympic Weightlifting (Snatch/Clean & Jerk). Use the one appropriate for your sport.
Does age affect the calculation?
The standard Wilks formula does not account for age. However, "Masters" coefficients (like the McCulloch coefficient) can be applied on top of Wilks to adjust for age-related decline.
What is the difference between Wilks and DOTS?
DOTS is a newer formula adopted by some federations to address biases in the Wilks formula, particularly regarding middle-heavyweight lifters. Wilks remains the most universally recognized historically.
Can I use this for Strongman?
Strongman does not typically use Wilks. However, it can give a rough estimate of static strength relative to size, but Strongman involves movement events not captured here.
How accurate is the female formula?
The female formula is specifically derived from female competition data to account for different strength-to-weight scaling laws in women compared to men.
Related Tools and Internal Resources
One Rep Max Calculator – Estimate your maximum lift potential based on sub-maximal repetitions.
RPE Calculator – Plan your training intensity using Rate of Perceived Exertion.
BMR Calculator – Calculate your Basal Metabolic Rate to understand your baseline energy burn.
Body Fat Calculator – Assess your body composition to improve your strength-to-weight ratio.
// Constants for Wilks Formula (Metric)
var MALE_COEFFS = {
a: -216.0475144,
b: 16.2606339,
c: -0.002388645,
d: -0.00113732,
e: 7.01863E-06,
f: -1.291E-08
};
var FEMALE_COEFFS = {
a: 594.31747775582,
b: -27.23842536447,
c: 0.82112226871,
d: -0.00930733913,
e: 4.731582E-05,
f: -9.054E-08
};
// Chart variable
var wilksChartInstance = null;
// Helper to get element
function getEl(id) {
return document.getElementById(id);
}
// Initialize
window.onload = function() {
calculateWilks();
};
function calculateWilks() {
var units = getEl("units").value;
var sex = getEl("gender").value;
var bwInput = parseFloat(getEl("bodyWeight").value);
var liftInput = parseFloat(getEl("liftedWeight").value);
// Validation
var isValid = true;
if (isNaN(bwInput) || bwInput <= 0) {
getEl("bwError").style.display = "block";
isValid = false;
} else {
getEl("bwError").style.display = "none";
}
if (isNaN(liftInput) || liftInput What you would lift if you were a heavyweight? No.
// Let's output "Old Wilks" vs "New Wilks 2020" difference? No too complex.
// Let's output a simple efficiency rating % relative to world record (approx 600)
var efficiency = (score / 600) * 100;
getEl("ipfPoints").innerText = efficiency.toFixed(1) + "%";
getEl("ipfPoints").nextElementSibling.innerText = "of World Record (Est)";
// Update Chart
updateChart(bwKg, liftKg, sex, score);
// Update Table
updateTable(bwKg, liftKg, score, sex, units);
}
function getClassification(score, sex) {
// Rough standards
if (score < 200) return "Beginner";
if (score < 300) return "Intermediate";
if (score < 400) return "Advanced";
if (score Lift = Score / Coeff
var x = bw; // already in kg
var cObj = (sex === "male") ? MALE_COEFFS : FEMALE_COEFFS;
var denom = cObj.a + (cObj.b * x) + (cObj.c * Math.pow(x, 2)) + (cObj.d * Math.pow(x, 3)) + (cObj.e * Math.pow(x, 4)) + (cObj.f * Math.pow(x, 5));
var coeff = 500 / denom;
var avgLiftKg = avgScore / coeff;
var eliteLiftKg = eliteScore / coeff;
// Convert back to display units
var displayLift = (units === "lbs") ? lift * 2.20462 : lift; // input was converted to kg for calc, if units is lbs, lift is in KG
// Wait, 'lift' passed to this function is 'liftKg' from calculateWilks
var userLiftDisplay = (units === "lbs") ? lift * 2.20462 : lift;
var avgLiftDisplay = (units === "lbs") ? avgLiftKg * 2.20462 : avgLiftKg;
var eliteLiftDisplay = (units === "lbs") ? eliteLiftKg * 2.20462 : eliteLiftKg;
// Rows
var html = "";
html += "
";
html += "
Total Lifted (" + unitLabel + ")
";
html += "
" + Math.round(userLiftDisplay) + "
";
html += "
" + Math.round(avgLiftDisplay) + "
";
html += "
" + Math.round(eliteLiftDisplay) + "
";
html += "
";
html += "
";
html += "
Wilks Score
";
html += "
" + score.toFixed(1) + "
";
html += "
" + avgScore + "
";
html += "
" + eliteScore + "
";
html += "
";
tbody.innerHTML = html;
}
// Canvas Chart Implementation (Native, No Libraries)
function updateChart(currentBw, currentLift, sex, currentScore) {
var canvas = getEl("wilksChart");
var ctx = canvas.getContext("2d");
// Handle High DPI
var dpr = window.devicePixelRatio || 1;
var rect = canvas.getBoundingClientRect();
canvas.width = rect.width * dpr;
canvas.height = rect.height * dpr;
ctx.scale(dpr, dpr);
var width = rect.width;
var height = rect.height;
var padding = 40;
ctx.clearRect(0, 0, width, height);
// Generate Data Points: Wilks Score vs Bodyweight (Fixed Lift)
// Range: Current BW +/- 20kg
var startBw = Math.max(40, currentBw – 15);
var endBw = currentBw + 15;
var dataPoints = [];
var cObj = (sex === "male") ? MALE_COEFFS : FEMALE_COEFFS;
var maxScore = 0;
var minScore = 1000;
for (var w = startBw; w maxScore) maxScore = s;
if (s < minScore) minScore = s;
}
// Add padding to scales
minScore = minScore * 0.95;
maxScore = maxScore * 1.05;
// Draw Axes
ctx.beginPath();
ctx.strokeStyle = "#ccc";
ctx.lineWidth = 1;
// Y Axis
ctx.moveTo(padding, padding);
ctx.lineTo(padding, height – padding);
// X Axis
ctx.lineTo(width – padding, height – padding);
ctx.stroke();
// Plot Line (Score vs BW)
ctx.beginPath();
ctx.strokeStyle = "#004a99";
ctx.lineWidth = 3;
var getX = function(bw) {
return padding + ((bw – startBw) / (endBw – startBw)) * (width – 2 * padding);
};
var getY = function(s) {
return (height – padding) – ((s – minScore) / (maxScore – minScore)) * (height – 2 * padding);
};
for (var i = 0; i < dataPoints.length; i++) {
var px = getX(dataPoints[i].bw);
var py = getY(dataPoints[i].score);
if (i === 0) ctx.moveTo(px, py);
else ctx.lineTo(px, py);
}
ctx.stroke();
// Draw Current User Point
var userX = getX(currentBw);
var userY = getY(currentScore);
ctx.beginPath();
ctx.fillStyle = "#28a745";
ctx.arc(userX, userY, 6, 0, 2 * Math.PI);
ctx.fill();
// Labels
ctx.fillStyle = "#333";
ctx.font = "12px sans-serif";
ctx.textAlign = "center";
// X Axis Label
ctx.fillText("Body Weight (kg)", width / 2, height – 5);
// Y Axis Label (Rotated)
ctx.save();
ctx.translate(15, height / 2);
ctx.rotate(-Math.PI / 2);
ctx.fillText("Wilks Score", 0, 0);
ctx.restore();
// Legend
ctx.fillStyle = "#004a99";
ctx.fillText("Score Trajectory", width – 80, padding);
ctx.fillStyle = "#28a745";
ctx.fillText("● You", width – 80, padding + 15);
}
// Initial resize handler for canvas
window.addEventListener('resize', function() {
calculateWilks();
});