Easily calculate Pounds per Square Inch (PSI) using weight and area. Understand the physics behind pressure with our interactive tool.
PSI Calculator
Enter the total weight acting on the surface (e.g., in pounds).
Enter the surface area over which the weight is distributed (e.g., in square inches).
Square Inches (in²)
Square Feet (ft²)
Square Centimeters (cm²)
Square Meters (m²)
Select the unit of measurement for the area.
Pounds (lbs)
Kilograms (kg)
Newtons (N)
Select the unit of measurement for the weight.
Calculation Results
— PSI
Force (Weight):—
Surface Area:—
Pressure Unit:PSI (Pounds per Square Inch)
Formula Used
Pressure (PSI) = Force (Weight) / Area
This formula calculates the intensity of force applied over a specific unit of area. When weight is distributed over a smaller area, the pressure exerted increases.
PSI vs. Weight & Area Analysis
Weight (lbs)Area (in²)Calculated PSI
Pressure changes as weight increases or area decreases.
What is PSI?
PSI stands for Pounds per Square Inch. It is a unit of pressure, commonly used in the United States and Canada, that measures the amount of force applied to one square inch of surface area. Understanding PSI is crucial in various fields, from engineering and mechanics to everyday applications like inflating tires or understanding fluid dynamics.
Essentially, PSI quantifies how concentrated a force is. A high PSI indicates a lot of force packed into a small area, while a low PSI means the same force is spread out over a larger area.
Who should use PSI calculations?
Engineers and Designers: To ensure materials and components can withstand calculated pressures without failing.
Mechanics and Technicians: For tasks like inflating tires to the correct pressure, checking hydraulic systems, or working with compressed air.
DIY Enthusiasts: When working on projects involving pressure, such as setting up pneumatic systems or understanding structural loads.
Physics Students: To grasp fundamental concepts of force, area, and pressure.
Common Misconceptions about PSI:
PSI is only about weight: While weight is a common source of force, any type of force (push, pull, impact) can be measured in PSI when applied over an area.
Higher weight always means higher PSI: This is incorrect. If the area increases proportionally with the weight, the PSI can remain constant. For example, spreading weight across a larger surface reduces pressure.
PSI is a measure of force itself: PSI is a measure of *pressure*, which is force *per unit area*. Force is measured in pounds or Newtons.
PSI Formula and Mathematical Explanation
The fundamental formula for calculating PSI is straightforward:
Pressure (PSI) = Force (Weight) / Area
Let's break down the components:
Force (Weight): This is the total downward force being exerted. In many practical scenarios, this force is the weight of an object or system. It is typically measured in pounds (lbs) for PSI calculations. If your weight is in kilograms, you'll need to convert it to pounds (1 kg ≈ 2.20462 lbs) or Newtons and then convert the final PSI if needed.
Area: This is the specific surface area over which the force is applied. For PSI, this area MUST be in square inches (in²). If your area is given in other units like square feet or square centimeters, conversion is necessary.
Derivation: Imagine placing a book flat on a table. The weight of the book is distributed across the entire bottom surface area of the book. Now, imagine balancing that same book on its spine. The weight is the same, but the area of contact is much smaller. The pressure exerted on the table is significantly higher when balanced on the spine because the same force is concentrated over a smaller area.
Variable Explanations Table
Variable
Meaning
Unit
Typical Range
Weight (Force)
The total mass or load applied vertically.
Pounds (lbs) or Kilograms (kg)
Varies widely (e.g., 1 lb to thousands of lbs)
Area
The surface area over which the weight is distributed.
Square Inches (in²)
Varies widely (e.g., 0.1 in² to thousands of in²)
PSI (Pressure)
Pounds per Square Inch – the resulting pressure.
Pounds per Square Inch (psi)
Can range from fractions of a psi to millions (e.g., 1 psi to 10,000+ psi)
Practical Examples (Real-World Use Cases)
Example 1: Tire Pressure
A common application is checking tire pressure. Let's say a car tire has a contact patch with the road measuring 5 inches by 6 inches. The total weight supported by this tire is 800 lbs.
Interpretation: The pressure exerted by the car's weight on this specific tire's contact area is approximately 26.67 PSI. Tire manufacturers often recommend specific PSI ranges for optimal performance, fuel efficiency, and safety.
Example 2: Shoe Heel Pressure
Consider someone weighing 150 lbs wearing high heels. If the heel tip has a surface area of just 0.5 square inches.
Weight: 150 lbs
Area: 0.5 in²
Calculation: PSI = 150 lbs / 0.5 in² = 300 PSI
Interpretation: The pressure under the heel tip is a very high 300 PSI. Compare this to someone weighing the same 150 lbs wearing flat shoes with a larger sole area, say 30 square inches. The PSI would be 150 lbs / 30 in² = 5 PSI. This dramatic difference in PSI explains why high heels can cause damage to certain surfaces (like wooden floors or turf) and exert significant pressure on the wearer's feet.
How to Use This PSI Calculator
Our free PSI calculator simplifies the process of determining pressure. Follow these steps:
Enter the Weight: Input the total weight or force you want to calculate the pressure for. Ensure you select the correct weight unit (e.g., pounds, kilograms).
Enter the Area: Provide the surface area over which this weight is distributed. Accuracy here is key.
Select Area Units: Choose the unit of measurement for your area input (e.g., square inches, square feet). The calculator will automatically convert it to square inches for the PSI calculation.
Select Weight Units: Choose the unit of measurement for your weight input. The calculator will convert it to pounds if necessary.
Click 'Calculate PSI': The calculator will instantly display the primary result in PSI.
Review Intermediate Values: Check the displayed force (weight) and surface area values to ensure they match your inputs and conversions.
Interpret the Results: Understand what the calculated PSI means in your specific context. Use the 'Copy Results' button to save or share the details.
How to read results: The main result is the calculated pressure in Pounds per Square Inch (PSI). The intermediate values confirm the inputs used, and the formula explanation clarifies the calculation. Use this information to make informed decisions about material strength, tire inflation, or any application where pressure is a factor.
Decision-making guidance: A high PSI might indicate a need for stronger materials, a larger contact area to distribute force, or adjustments to reduce pressure. Conversely, a low PSI might be suitable or even desirable in certain applications.
Key Factors That Affect PSI Results
Several factors influence the calculated PSI, and understanding them is vital for accurate interpretation:
Magnitude of Weight (Force): This is the most direct factor. A heavier object or a greater applied force will result in higher PSI, assuming the area remains constant.
Surface Area of Contact: This is the inverse factor. A smaller area of contact for the same weight leads to significantly higher PSI. This is why sharp objects can cut easily, and wide snowshoes allow you to walk on snow without sinking as much.
Units of Measurement: Inconsistent or incorrect units are a primary source of error. Ensuring weight is in pounds and area is in square inches (or using conversions correctly) is critical for accurate PSI calculation. The calculator handles conversions for common units.
Distribution of Load: Even within a given area, how the weight is distributed matters. A concentrated load in one part of the area will create higher local PSI than a uniformly distributed load.
Material Properties: While not directly in the PSI formula, the material's ability to withstand pressure (its compressive strength) is crucial. A high PSI calculation might be theoretically possible, but the material might fail if its strength is exceeded.
Dynamic vs. Static Forces: The calculator typically assumes static weight. However, dynamic forces (like impacts or vibrations) can create much higher peak pressures than the static weight alone would suggest.
Environmental Factors: Temperature can affect materials and fluid pressures. For instance, air pressure in tires increases slightly as temperature rises.
Fluid Pressure Dynamics: In fluid systems, factors like flow rate, viscosity, and system resistance contribute to pressure (PSI) readings, which go beyond simple weight-on-area calculations.
Frequently Asked Questions (FAQ)
What's the difference between PSI and Force?
Force is the total push or pull (measured in pounds or Newtons). PSI (Pressure) is that force distributed over a specific area (pounds per square inch). You can have a large force with low PSI if spread over a large area, or a small force with high PSI if concentrated on a tiny area.
Do I need to convert my weight from kilograms to pounds?
Yes, if you want the result directly in PSI (Pounds per Square Inch). Our calculator includes a unit converter for weight, so you can input kilograms and it will convert to pounds internally before calculating PSI.
My area is in square feet. How do I convert it for PSI?
There are 144 square inches in 1 square foot (12 inches * 12 inches). So, multiply your area in square feet by 144 to get the equivalent in square inches. Our calculator handles this conversion automatically based on your selection.
Can PSI be negative?
In the context of weight applied to an area, PSI is typically positive. Negative pressure usually refers to conditions where the pressure is below atmospheric pressure (a vacuum or partial vacuum), or in specific fluid dynamics contexts involving tension.
What is a "safe" PSI value?
There is no universal "safe" PSI. It entirely depends on the application. For example, car tire PSI is typically 30-40, while industrial hydraulic systems can operate at thousands of PSI. You must consult specifications relevant to your particular use case.
Does altitude affect PSI?
Altitude primarily affects atmospheric pressure. While the gauge pressure in a tire might read the same, the absolute pressure (including atmospheric) will be lower at higher altitudes. For most ground-level applications, this effect is negligible, but it's a factor in aviation and high-altitude engineering.
How does the calculator handle different units?
The calculator allows you to select units for both weight and area. It internally converts these to pounds and square inches, respectively, to perform the standard PSI calculation. It then displays the converted weight and area values for clarity.
Can I use this for fluid pressure?
This calculator is primarily designed for static weight applied over an area. While the core formula (Pressure = Force/Area) applies to fluids, fluid pressure calculations can be more complex, involving factors like fluid density, height (head pressure), and flow dynamics. This tool is best suited for direct weight-based pressure calculations.
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var weightInput = document.getElementById('weight');
var areaInput = document.getElementById('area');
var areaUnitSelect = document.getElementById('areaUnit');
var weightUnitSelect = document.getElementById('weightUnit');
var primaryResultDisplay = document.getElementById('primary-result');
var displayWeightDisplay = document.getElementById('displayWeight');
var displayAreaDisplay = document.getElementById('displayArea');
var displayPressureUnitDisplay = document.getElementById('displayPressureUnit');
var weightError = document.getElementById('weightError');
var areaError = document.getElementById('areaError');
var chart = null;
var chartContext = null;
var myChartInstance = null;
// Constants for unit conversions
var LBS_PER_KG = 2.20462;
var SQ_IN_PER_SQ_FT = 144;
var SQ_IN_PER_SQ_M = 1550.0031;
var SQ_IN_PER_SQ_CM = 0.15500031;
function convertWeightToLbs(weight, unit) {
if (unit === 'kg') {
return weight * LBS_PER_KG;
} else if (unit === 'newtons') {
// Approximate conversion: Force (lbs) = Force (N) / 4.44822
// For simplicity, we'll assume standard gravity if Newtons are used,
// but usually, weight in lbs or kg is more direct.
// A more accurate approach needs mass and gravity, but for this calculator,
// we'll use a direct conversion often found in simplified contexts.
return weight / 4.44822; // This assumes Newtons are used as a weight equivalent
}
return weight; // Default to lbs
}
function convertAreaToSqIn(area, unit) {
if (unit === 'sq_ft') {
return area * SQ_IN_PER_SQ_FT;
} else if (unit === 'sq_cm') {
return area * SQ_IN_PER_SQ_CM;
} else if (unit === 'sq_m') {
return area * SQ_IN_PER_SQ_M;
}
return area; // Default to sq_in
}
function calculatePSI() {
// Clear previous errors
weightError.style.display = 'none';
areaError.style.display = 'none';
var weightValue = parseFloat(weightInput.value);
var areaValue = parseFloat(areaInput.value);
var weightUnit = weightUnitSelect.value;
var areaUnit = areaUnitSelect.value;
var valid = true;
if (isNaN(weightValue) || weightValue <= 0) {
weightError.textContent = 'Please enter a valid positive weight.';
weightError.style.display = 'block';
valid = false;
}
if (isNaN(areaValue) || areaValue <= 0) {
areaError.textContent = 'Please enter a valid positive area.';
areaError.style.display = 'block';
valid = false;
}
if (!valid) {
// Reset results if inputs are invalid
primaryResultDisplay.textContent = '– PSI';
displayWeightDisplay.textContent = '–';
displayAreaDisplay.textContent = '–';
updateChart([], []); // Clear chart
return;
}
var weightInLbs = convertWeightToLbs(weightValue, weightUnit);
var areaInSqIn = convertAreaToSqIn(areaValue, areaUnit);
var psi = weightInLbs / areaInSqIn;
primaryResultDisplay.textContent = psi.toFixed(2) + ' PSI';
displayWeightDisplay.textContent = weightValue.toFixed(2) + ' ' + weightUnit;
displayAreaDisplay.textContent = areaValue.toFixed(2) + ' ' + areaUnit;
displayPressureUnitDisplay.textContent = 'PSI (Pounds per Square Inch)';
// Update chart data
updateChartData(weightValue, areaValue, psi, weightUnit, areaUnit);
}
function resetCalculator() {
weightInput.value = 150; // Sensible default weight (lbs)
areaInput.value = 2; // Sensible default area (sq in)
weightUnitSelect.value = 'lbs';
areaUnitSelect.value = 'sq_in';
// Clear errors
weightError.style.display = 'none';
areaError.style.display = 'none';
calculatePSI(); // Recalculate with defaults
}
function copyResults() {
var primaryResult = primaryResultDisplay.textContent;
var force = displayWeightDisplay.textContent;
var area = displayAreaDisplay.textContent;
var pressureUnit = displayPressureUnitDisplay.textContent;
var assumptions = "Key Assumptions:\n" +
"- Weight Units: " + weightUnitSelect.options[weightUnitSelect.selectedIndex].text + "\n" +
"- Area Units: " + areaUnitSelect.options[areaUnitSelect.selectedIndex].text + "\n";
var textToCopy = "PSI Calculation Results:\n" +
"Pressure: " + primaryResult + "\n" +
"Force (Weight): " + force + "\n" +
"Surface Area: " + area + "\n" +
"Pressure Unit: " + pressureUnit + "\n\n" +
assumptions;
navigator.clipboard.writeText(textToCopy).then(function() {
// Optional: Provide user feedback
var originalText = this.textContent;
this.textContent = 'Copied!';
setTimeout(function() {
this.textContent = originalText;
}.bind(this), 2000);
}.bind(event.target)).catch(function(err) {
console.error('Could not copy text: ', err);
// Fallback for browsers that don't support clipboard API well
alert('Could not copy. Please manually select and copy the text.');
});
}
function toggleFaq(element) {
var content = element.nextElementSibling;
if (content.style.display === "block") {
content.style.display = "none";
} else {
content.style.display = "block";
}
}
// Charting Logic
function setupChart() {
chartContext = document.getElementById('myChart').getContext('2d');
myChartInstance = new Chart(chartContext, {
type: 'line',
data: {
labels: [], // Will be populated dynamically
datasets: [
{
label: 'Weight',
data: [], // Dynamic
borderColor: 'rgb(0, 123, 255)', // Blue
backgroundColor: 'rgba(0, 123, 255, 0.1)',
fill: false,
yAxisID: 'y-axis-weight',
tension: 0.1
},
{
label: 'Area',
data: [], // Dynamic
borderColor: 'rgb(255, 193, 7)', // Yellow
backgroundColor: 'rgba(255, 193, 7, 0.1)',
fill: false,
yAxisID: 'y-axis-area',
tension: 0.1
},
{
label: 'Calculated PSI',
data: [], // Dynamic
borderColor: 'rgb(40, 167, 69)', // Green
backgroundColor: 'rgba(40, 167, 69, 0.1)',
fill: false,
yAxisID: 'y-axis-psi',
tension: 0.1
}
]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
x: {
title: {
display: true,
text: 'Input Values (Varies)'
}
},
'y-axis-weight': {
type: 'linear',
position: 'left',
title: {
display: true,
text: 'Weight (' + weightUnitSelect.value + ')'
},
grid: {
drawOnChartArea: false, // Only draw grid lines for the first y-axis
}
},
'y-axis-area': {
type: 'linear',
position: 'left', // Stacking on the left
title: {
display: true,
text: 'Area (' + areaUnitSelect.value + ')'
},
grid: {
drawOnChartArea: false,
},
// Offset this axis slightly to prevent overlap with the first Y axis
ticks: {
// You might need to adjust padding or manually calculate offsets if overlap is severe
}
},
'y-axis-psi': {
type: 'linear',
position: 'right',
title: {
display: true,
text: 'PSI'
}
}
},
plugins: {
legend: {
display: false // Legend is handled by custom div
},
tooltip: {
mode: 'index',
intersect: false,
}
},
hover: {
mode: 'nearest',
intersect: true
}
}
});
}
function updateChartData(currentWeight, currentArea, currentPsi, weightUnit, areaUnit) {
if (!myChartInstance) {
setupChart();
}
// Define range for chart data generation
// We'll simulate changes by varying one input while keeping the other fixed
var baseWeight = convertWeightToLbs(parseFloat(weightInput.value), weightUnitSelect.value);
var baseArea = convertAreaToSqIn(parseFloat(areaInput.value), areaUnitSelect.value);
var weightData = [];
var areaData = [];
var psiData = [];
var labels = [];
var steps = 10; // Number of data points for the chart
// Scenario 1: Vary Weight, Keep Area Constant
var fixedAreaSqIn = baseArea;
if (fixedAreaSqIn <= 0) fixedAreaSqIn = 1; // Prevent division by zero
for (var i = 1; i <= steps; i++) {
var weightMultiplier = i / steps;
var simulatedWeightLbs = baseWeight * weightMultiplier;
var simulatedWeightValue = parseFloat(weightInput.value) * weightMultiplier;
var simulatedPsi = simulatedWeightLbs / fixedAreaSqIn;
labels.push("W: " + simulatedWeightValue.toFixed(0) + " " + weightUnit);
weightData.push(simulatedWeightLbs);
areaData.push(fixedAreaSqIn); // Constant area
psiData.push(simulatedPsi);
}
// Scenario 2: Vary Area, Keep Weight Constant
var fixedWeightLbs = baseWeight;
if (fixedWeightLbs <= 0) fixedWeightLbs = 1; // Prevent division by zero
// We need a new set of labels for the second scenario if we want to show both clearly on the same X-axis
// Or, we can adjust the X-axis label to be generic like 'Change Factor' and rely on Y-axes interpretation.
// For simplicity, let's create a combined dataset or adjust the scenario.
// Let's simulate changing *one* variable while the other is held at its *original* input value.
// Reset data arrays
weightData = [];
areaData = [];
psiData = [];
labels = [];
// Generate data points: Let's vary weight from 50% to 150% of the input
var minWeight = baseWeight * 0.5;
var maxWeight = baseWeight * 1.5;
if (minWeight <= 0) minWeight = 1; // Ensure positive
for (var i = 0; i <= steps; i++) {
var weightRatio = i / steps;
var currentSimulatedWeightLbs = minWeight + (maxWeight – minWeight) * weightRatio;
var currentSimulatedWeightValue = parseFloat(weightInput.value) * (currentSimulatedWeightLbs / baseWeight);
var currentSimulatedPsi = currentSimulatedWeightLbs / baseArea;
labels.push("Weight " + currentSimulatedWeightValue.toFixed(0) + " " + weightUnit);
weightData.push(currentSimulatedWeightLbs);
areaData.push(baseArea);
psiData.push(currentSimulatedPsi);
}
// Add a second series: Vary Area, Keep Weight Constant
// Let's vary area from 50% to 150% of the input
var minArea = baseArea * 0.5;
var maxArea = baseArea * 1.5;
if (minArea <= 0) minArea = 1; // Ensure positive
var areaLabels = [];
var areaSeriesWeightData = []; // Weight data for the area variation scenario (constant)
var areaSeriesAreaData = [];
var areaSeriesPsiData = [];
for (var i = 0; i 0 ? initialAreaSqIn : 1;
for (var i = 0; i 0 ? initialWeightLbs : 1;
var areaLabels = [];
var areaWeights = []; // Constant weight for this series
var areaAreas = [];
var areaPsis = [];
for (var i = 0; i < 10; i++) {
var areaFactor = 0.5 + (i / 9) * 1.0; // Varies from 0.5x to 1.5x initial area
var currentArea = initialAreaSqIn * areaFactor;
var currentPsi = weightForChart2 / currentArea;
areaLabels.push('Area (' + (initialAreaSqIn * areaFactor).toFixed(0) + ' ' + areaUnitSelect.value + ')');
areaWeights.push(weightForChart2); // Fixed weight
areaAreas.push(currentArea);
areaPsis.push(currentPsi);
}
// Decide how to display: overlaying can be confusing if scales differ wildly.
// Let's make the chart show two lines:
// Line 1: PSI when weight changes, area is fixed. X-axis: Weight value.
// Line 2: PSI when area changes, weight is fixed. X-axis: Area value.
// This requires careful axis setup or potentially separate charts.
// Simplest approach for a single chart: Use a generic X-axis representing "change factor" and rely on tooltips.
// Or, plot PSI vs Weight (with Area fixed) AND PSI vs Area (with Weight fixed) on the same chart.
// Let's try overlaying:
// Series 1: PSI vs Weight change
// Series 2: PSI vs Area change
// X-axis can be generic "Scenario Point"
myChartInstance.data.labels = []; // Clear previous labels
myChartInstance.data.datasets[0].data = [];
myChartInstance.data.datasets[1].data = [];
myChartInstance.data.datasets[2].data = [];
// Populate datasets for weight variation
var weightLabels = [];
var weightSeriesPsi = [];
var weightSeriesWeight = []; // Store weight value for tooltip
var weightSeriesArea = []; // Store fixed area value for tooltip
for (var i = 0; i < 10; i++) {
var weightFactor = 0.5 + (i / 9) * 1.0;
var currentWeight = initialWeightLbs * weightFactor;
var currentPsi = currentWeight / areaForChart1;
weightLabels.push(i + 1); // Generic point number
weightSeriesPsi.push(currentPsi);
weightSeriesWeight.push(currentWeight);
weightSeriesArea.push(areaForChart1);
}
// Populate datasets for area variation
var areaLabels = [];
var areaSeriesPsi = [];
var areaSeriesWeight = []; // Store fixed weight value for tooltip
var areaSeriesArea = []; // Store area value for tooltip
for (var i = 0; i < 10; i++) {
var areaFactor = 0.5 + (i / 9) * 1.0;
var currentArea = initialAreaSqIn * areaFactor;
var currentPsi = weightForChart2 / currentArea;
areaLabels.push(i + 1); // Generic point number, but distinct from weight labels if possible
areaSeriesPsi.push(currentPsi);
areaSeriesWeight.push(weightForChart2);
areaSeriesArea.push(currentArea);
}
// Update chart datasets for overlay
myChartInstance.data.labels = Array.apply(null, {length: 10}).map(Number.call, Number); // Simple 1-10 labels
myChartInstance.data.datasets[0].data = weightSeriesPsi; // PSI from weight variation
myChartInstance.data.datasets[0].label = 'PSI (Weight Varying)';
myChartInstance.data.datasets[0].yAxisID = 'y-axis-psi';
myChartInstance.data.datasets[0].borderColor = 'rgb(0, 123, 255)'; // Blue
myChartInstance.data.datasets[0].backgroundColor = 'rgba(0, 123, 255, 0.1)';
myChartInstance.data.datasets[1].data = areaSeriesPsi; // PSI from area variation
myChartInstance.data.datasets[1].label = 'PSI (Area Varying)';
myChartInstance.data.datasets[1].yAxisID = 'y-axis-psi';
myChartInstance.data.datasets[1].borderColor = 'rgb(255, 193, 7)'; // Yellow
myChartInstance.data.datasets[1].backgroundColor = 'rgba(255, 193, 7, 0.1)';
// Remove or hide the weight/area lines, focus on PSI changes
myChartInstance.data.datasets[2].data = []; // Clear the third dataset (placeholder)
// Update axis labels dynamically
myChartInstance.options.scales['y-axis-weight'].title.text = 'Weight (' + weightUnitSelect.value + ')';
myChartInstance.options.scales['y-axis-area'].title.text = 'Area (' + areaUnitSelect.value + ')';
// Custom tooltip to show the context
myChartInstance.options.plugins.tooltip.callbacks = {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += context.parsed.y.toFixed(2) + ' PSI';
}
var index = context.dataIndex;
var originalWeight = parseFloat(weightInput.value);
var originalArea = parseFloat(areaInput.value);
var initialWeightLbs = convertWeightToLbs(originalWeight, weightUnitSelect.value);
var initialAreaSqIn = convertAreaToSqIn(originalArea, areaUnitSelect.value);
if (context.dataset.label.includes('Weight Varying')) {
var weightFactor = 0.5 + (index / 9) * 1.0;
var currentWeight = initialWeightLbs * weightFactor;
var currentArea = initialAreaSqIn; // Fixed area
label += '\n (Weight: ' + currentWeight.toFixed(0) + ' ' + weightUnitSelect.value + ', Area: ' + currentArea.toFixed(2) + ' ' + areaUnitSelect.value + ')';
} else if (context.dataset.label.includes('Area Varying')) {
var areaFactor = 0.5 + (index / 9) * 1.0;
var currentArea = initialAreaSqIn * areaFactor;
var currentWeight = initialWeightLbs; // Fixed weight
label += '\n (Weight: ' + currentWeight.toFixed(0) + ' ' + weightUnitSelect.value + ', Area: ' + currentArea.toFixed(0) + ' ' + areaUnitSelect.value + ')';
}
return label;
}
};
myChartInstance.update();
}
// Initialize chart on load
window.onload = function() {
resetCalculator(); // Set defaults and calculate initial values
setupChart(); // Setup the chart structure
updateChartData(); // Populate chart with initial data
};
// Update chart dynamically when inputs change
weightInput.addEventListener('input', updateChartData);
areaInput.addEventListener('input', updateChartData);
weightUnitSelect.addEventListener('change', updateChartData);
areaUnitSelect.addEventListener('change', updateChartData);