Hexagon Rod Weight Calculator | Professional Metal Weight Estimator
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Total Estimated Weight
0.00 kg
Weight Per Piece:
–
Cross-Sectional Area:
–
Total Volume:
–
Material Density Used:
–
Formula: Weight = (0.866 × Width²) × Length × Density
Shape Comparison (Weight)
Comparison of a Hexagon rod vs. Round and Square rods of the same dimension (Width/Diameter).
Specification Summary
| Parameter |
Value |
| Material | – |
| Width (A/F) | – |
| Length | – |
| Quantity | – |
| Total Weight | – |
What is a Hexagon Rod Weight Calculator?
A hexagon rod weight calculator is a specialized engineering tool designed to estimate the mass of hexagonal metal bars based on their dimensions and material properties. Unlike simple square or round bars, hexagonal rods (often called hex bars) have a six-sided cross-section, which requires a specific geometric formula to calculate volume and weight accurately.
This tool is essential for machinists, structural engineers, procurement officers, and logistics planners who need to determine shipping costs, structural loads, or material requirements for projects involving hex fasteners, shafts, or custom fittings.
Hexagon Rod Weight Calculator Formula
To calculate the weight of a hexagonal rod, we must first determine the cross-sectional area of the hexagon and then multiply it by the length and the material density. The critical dimension is the "Width Across Flats" (A/F), which is the distance between two parallel opposite sides.
The Mathematical Derivation
The area ($A$) of a regular hexagon can be derived from the Width Across Flats ($W$):
Area = (√3 / 2) × W² ≈ 0.866025 × W²
Once the area is known, the total weight is calculated as:
Weight = Area × Length × Density
Variables Table
| Variable |
Meaning |
Metric Unit |
Imperial Unit |
| W |
Width Across Flats |
Millimeters (mm) |
Inches (in) |
| L |
Length of Rod |
Meters (m) |
Feet (ft) |
| ρ (Rho) |
Material Density |
g/cm³ or kg/m³ |
lbs/in³ |
Practical Examples
Example 1: Steel Hex Bar for Machining
A machine shop needs to order 50 pieces of Mild Steel hex bar. Each bar is 25mm across flats and 3 meters long.
- Material: Mild Steel (Density ~7.85 g/cm³)
- Width (W): 25 mm = 2.5 cm
- Length (L): 3 m = 300 cm
- Area: 0.866 × (2.5)² = 5.4125 cm²
- Volume per bar: 5.4125 cm² × 300 cm = 1623.75 cm³
- Weight per bar: 1623.75 × 7.85 = 12,746 g = 12.75 kg
- Total Weight (50 pcs): 12.75 kg × 50 = 637.5 kg
Example 2: Brass Hex Standoffs
An electronics manufacturer requires 1000 small brass standoffs. The raw stock is 0.5 inches wide and 12 feet long.
- Material: Brass (Density ~0.307 lbs/in³)
- Width (W): 0.5 in
- Length (L): 12 ft = 144 in
- Area: 0.866 × (0.5)² = 0.2165 in²
- Volume: 0.2165 in² × 144 in = 31.176 in³
- Weight per bar: 31.176 × 0.307 = 9.57 lbs
How to Use This Hexagon Rod Weight Calculator
- Select Unit System: Choose between Metric (mm/kg) or Imperial (inches/lbs) based on your supplier's specifications.
- Choose Material: Select the metal type from the dropdown. If your material isn't listed, select "Custom" and enter the specific density.
- Enter Dimensions: Input the "Width Across Flats" (not corner-to-corner) and the total length of the rod.
- Set Quantity: Enter the number of pieces you intend to purchase or manufacture.
- Review Results: The calculator instantly updates the total weight, weight per piece, and volume. Use the "Copy Results" button to save the data for your records.
Key Factors That Affect Hexagon Rod Weight
When using a hexagon rod weight calculator, consider these factors that can influence the final calculation and real-world application:
- Material Density Variations: Different alloys of the same metal (e.g., SS 304 vs. SS 316) have slightly different densities. Always check the specific alloy grade.
- Dimensional Tolerances: Manufacturing tolerances means a "25mm" bar might actually be 25.1mm or 24.9mm. Over thousands of meters, this affects total tonnage.
- Corner Radius: Some hex bars have rounded corners rather than sharp edges, slightly reducing the actual volume and weight compared to the theoretical formula.
- Surface Finish & Coating: Plating (zinc, chrome) or heavy oxidation adds a negligible amount of weight but can affect precise fitment.
- Scrap & Kerf Loss: If you are calculating weight to determine how many parts you can make, remember to account for material lost during cutting (kerf).
- Cost Implications: Metals are sold by weight. A 1% error in weight calculation on a large order of Titanium or Copper can result in significant financial discrepancies.
Frequently Asked Questions (FAQ)
Is the width measured across flats or corners?
Standard hex bars are measured "Across Flats" (A/F). This is the distance between two parallel flat surfaces where a wrench would fit. Measuring across corners will result in an incorrect, larger area calculation.
How does a hex bar compare to a round bar in weight?
A hex bar is heavier than a round bar of the same diameter (where diameter = width across flats). A hex bar covers approximately 10% more cross-sectional area than a circle inscribed within it.
Can I calculate the weight of a hollow hex rod?
This calculator assumes a solid rod. For a hollow hex rod, calculate the weight of the solid outer hex and subtract the weight of the inner hole (usually round) separately.
What is the density of mild steel?
Mild steel typically has a density of roughly 7.85 g/cm³ or 0.284 lbs/in³. This is the industry standard default for steel weight calculations.
Why is my result slightly different from the supplier's shipping weight?
Supplier weights often include packaging (pallets, straps, wrap) and may round up. Additionally, actual material density can vary slightly by batch.
Does this calculator work for plastic hex rods?
Yes. Select "Custom Density" and enter the density of the plastic (e.g., Nylon is approx 1.15 g/cm³, Delrin is 1.41 g/cm³).
How do I convert meters to feet for this calculator?
1 meter equals approximately 3.28084 feet. If you switch the unit system to "Imperial", you can enter feet directly.
What is the formula for the volume of a hexagonal prism?
Volume = Area of Base × Height. For a hex rod, Volume = (0.866 × Width²) × Length.
Related Tools and Internal Resources
Explore our other engineering and material calculators:
// Global Variables
var currentUnit = 'metric'; // 'metric' or 'imperial'
var chartInstance = null;
// DOM Elements
var elUnitSystem = document.getElementById('unitSystem');
var elMaterial = document.getElementById('material');
var elCustomDensityGroup = document.getElementById('customDensityGroup');
var elCustomDensity = document.getElementById('customDensity');
var elWidth = document.getElementById('hexWidth');
var elLength = document.getElementById('rodLength');
var elQuantity = document.getElementById('quantity');
// Labels
var lblDensity = document.getElementById('densityLabel');
var lblWidth = document.getElementById('widthLabel');
var lblLength = document.getElementById('lengthLabel');
// Results
var resTotalWeight = document.getElementById('totalWeight');
var resWeightPerPiece = document.getElementById('weightPerPiece');
var resCrossArea = document.getElementById('crossArea');
var resTotalVolume = document.getElementById('totalVolume');
var resDensityUsed = document.getElementById('densityUsed');
// Table Cells
var tblMaterial = document.getElementById('tblMaterial');
var tblWidth = document.getElementById('tblWidth');
var tblLength = document.getElementById('tblLength');
var tblQty = document.getElementById('tblQty');
var tblWeight = document.getElementById('tblWeight');
// Canvas
var canvas = document.getElementById('weightChart');
var ctx = canvas.getContext('2d');
// Initialization
window.onload = function() {
// Attach listeners
var inputs = [elMaterial, elCustomDensity, elWidth, elLength, elQuantity];
for (var i = 0; i < inputs.length; i++) {
inputs[i].addEventListener('input', calculate);
}
// Initial calc
updateUnits();
};
function updateUnits() {
currentUnit = elUnitSystem.value;
if (currentUnit === 'metric') {
lblWidth.innerText = 'Width Across Flats (mm)';
lblLength.innerText = 'Length (meters)';
lblDensity.innerText = 'Custom Density (g/cm³)';
elWidth.placeholder = 'e.g., 25';
elLength.placeholder = 'e.g., 3';
} else {
lblWidth.innerText = 'Width Across Flats (inches)';
lblLength.innerText = 'Length (feet)';
lblDensity.innerText = 'Custom Density (lbs/in³)';
elWidth.placeholder = 'e.g., 1.0';
elLength.placeholder = 'e.g., 10';
}
// Reset values to sensible defaults for the unit system
if (currentUnit === 'metric') {
elWidth.value = 25;
elLength.value = 1;
} else {
elWidth.value = 1;
elLength.value = 3;
}
handleMaterialChange(); // Updates density label if custom
calculate();
}
function handleMaterialChange() {
var val = elMaterial.value;
if (val === 'custom') {
elCustomDensityGroup.classList.remove('hidden');
} else {
elCustomDensityGroup.classList.add('hidden');
}
calculate();
}
function resetCalculator() {
elQuantity.value = 1;
elMaterial.value = "7.85";
handleMaterialChange();
updateUnits(); // Resets width/length based on unit
}
function calculate() {
// 1. Get Values
var width = parseFloat(elWidth.value);
var length = parseFloat(elLength.value);
var qty = parseInt(elQuantity.value);
var density = 0;
// 2. Validation
var isValid = true;
if (isNaN(width) || width <= 0) {
document.getElementById('widthError').style.display = 'block';
isValid = false;
} else {
document.getElementById('widthError').style.display = 'none';
}
if (isNaN(length) || length <= 0) {
document.getElementById('lengthError').style.display = 'block';
isValid = false;
} else {
document.getElementById('lengthError').style.display = 'none';
}
if (isNaN(qty) || qty < 1) {
document.getElementById('qtyError').style.display = 'block';
isValid = false;
} else {
document.getElementById('qtyError').style.display = 'none';
}
// Density Logic
if (elMaterial.value === 'custom') {
density = parseFloat(elCustomDensity.value);
if (isNaN(density) || density <= 0) {
document.getElementById('densityError').style.display = 'block';
isValid = false;
} else {
document.getElementById('densityError').style.display = 'none';
}
} else {
density = parseFloat(elMaterial.value);
// If imperial, convert the stored metric density (g/cm3) to lbs/in3 for calculation logic
// Or better: Normalize everything to Metric for calculation, then convert back.
// Let's normalize inputs to cm and g.
}
if (!isValid) return;
// 3. Normalization to Metric (cm, g)
var widthCm, lengthCm, densityGcm3;
if (currentUnit === 'metric') {
widthCm = width / 10; // mm to cm
lengthCm = length * 100; // m to cm
if (elMaterial.value === 'custom') {
densityGcm3 = density;
} else {
densityGcm3 = density; // Value in option is already g/cm3
}
} else {
// Imperial
widthCm = width * 2.54; // in to cm
lengthCm = length * 12 * 2.54; // ft to cm
if (elMaterial.value === 'custom') {
// Input is lbs/in3. Convert to g/cm3
// 1 lb = 453.592 g
// 1 in3 = 16.387 cm3
// Factor = 453.592 / 16.387 = 27.68
densityGcm3 = density * 27.68;
} else {
densityGcm3 = density; // Option values are always g/cm3
}
}
// 4. Calculation
// Hex Area = 0.866025 * w^2
var areaCm2 = 0.866025 * Math.pow(widthCm, 2);
var volumeCm3 = areaCm2 * lengthCm;
var weightG = volumeCm3 * densityGcm3;
var totalWeightG = weightG * qty;
// Comparison Calculations (for chart)
// Round Bar (Diameter = Width)
var roundArea = Math.PI * Math.pow(widthCm / 2, 2);
var roundWeight = roundArea * lengthCm * densityGcm3 * qty;
// Square Bar (Side = Width)
var squareArea = Math.pow(widthCm, 2);
var squareWeight = squareArea * lengthCm * densityGcm3 * qty;
// 5. Display Results
var displayWeight, displayUnit, displayArea, displayAreaUnit, displayVol, displayVolUnit, displayDensity;
if (currentUnit === 'metric') {
displayWeight = (totalWeightG / 1000).toFixed(2); // kg
displayUnit = 'kg';
displayArea = areaCm2.toFixed(2);
displayAreaUnit = 'cm²';
displayVol = (volumeCm3 * qty).toFixed(2);
displayVolUnit = 'cm³';
displayDensity = densityGcm3.toFixed(2) + ' g/cm³';
resWeightPerPiece.innerText = (weightG / 1000).toFixed(2) + ' kg';
} else {
// Convert g to lbs
var totalLbs = totalWeightG * 0.00220462;
displayWeight = totalLbs.toFixed(2);
displayUnit = 'lbs';
// Area cm2 to in2
displayArea = (areaCm2 / 6.4516).toFixed(3);
displayAreaUnit = 'in²';
// Vol cm3 to in3
displayVol = ((volumeCm3 * qty) / 16.387).toFixed(2);
displayVolUnit = 'in³';
// Density
var densityLbsIn3 = densityGcm3 / 27.68;
displayDensity = densityLbsIn3.toFixed(3) + ' lbs/in³';
resWeightPerPiece.innerText = (totalLbs / qty).toFixed(2) + ' lbs';
}
resTotalWeight.innerText = displayWeight + ' ' + displayUnit;
resCrossArea.innerText = displayArea + ' ' + displayAreaUnit;
resTotalVolume.innerText = displayVol + ' ' + displayVolUnit;
resDensityUsed.innerText = displayDensity;
// Update Table
var matName = elMaterial.options[elMaterial.selectedIndex].text;
if(elMaterial.value === 'custom') matName = "Custom";
tblMaterial.innerText = matName;
tblWidth.innerText = width + (currentUnit === 'metric' ? ' mm' : ' in');
tblLength.innerText = length + (currentUnit === 'metric' ? ' m' : ' ft');
tblQty.innerText = qty;
tblWeight.innerText = displayWeight + ' ' + displayUnit;
// 6. Draw Chart
drawChart(totalWeightG, roundWeight, squareWeight, currentUnit);
}
function drawChart(hexW, roundW, squareW, unit) {
// Clear canvas
ctx.clearRect(0, 0, canvas.width, canvas.height);
// Setup dimensions (simple responsive scaling)
var w = canvas.width = canvas.offsetWidth;
var h = canvas.height = canvas.offsetHeight;
var padding = 40;
var barWidth = (w – (padding * 2)) / 5;
var maxVal = Math.max(hexW, roundW, squareW) * 1.2; // 20% headroom
// Helper to convert value to Y pixel
function getY(val) {
return h – padding – ((val / maxVal) * (h – (padding * 2)));
}
// Draw Axes
ctx.beginPath();
ctx.moveTo(padding, padding);
ctx.lineTo(padding, h – padding);
ctx.lineTo(w – padding, h – padding);
ctx.strokeStyle = '#333';
ctx.stroke();
// Data
var data = [
{ label: 'Round', val: roundW, color: '#6c757d' },
{ label: 'Hexagon', val: hexW, color: '#004a99' }, // Highlighted
{ label: 'Square', val: squareW, color: '#6c757d' }
];
// Draw Bars
var startX = padding + barWidth/2;
for (var i = 0; i < data.length; i++) {
var d = data[i];
var barHeight = (d.val / maxVal) * (h – (padding * 2));
var x = startX + (i * (barWidth + 20));
var y = h – padding – barHeight;
// Bar
ctx.fillStyle = d.color;
ctx.fillRect(x, y, barWidth, barHeight);
// Label (Bottom)
ctx.fillStyle = '#333';
ctx.font = '14px Arial';
ctx.textAlign = 'center';
ctx.fillText(d.label, x + barWidth/2, h – padding + 20);
// Value (Top)
var valText = '';
if (unit === 'metric') valText = (d.val / 1000).toFixed(1) + ' kg';
else valText = (d.val * 0.00220462).toFixed(1) + ' lbs';
ctx.fillText(valText, x + barWidth/2, y – 10);
}
}
function copyResults() {
var text = "Hexagon Rod Weight Calculation\n";
text += "—————————-\n";
text += "Material: " + tblMaterial.innerText + "\n";
text += "Width (A/F): " + tblWidth.innerText + "\n";
text += "Length: " + tblLength.innerText + "\n";
text += "Quantity: " + tblQty.innerText + "\n";
text += "Total Weight: " + tblWeight.innerText + "\n";
text += "—————————-\n";
text += "Calculated via Hexagon Rod Weight Calculator";
var tempInput = document.createElement("textarea");
tempInput.value = text;
document.body.appendChild(tempInput);
tempInput.select();
document.execCommand("copy");
document.body.removeChild(tempInput);
var btn = document.querySelector('.btn-copy');
var originalText = btn.innerText;
btn.innerText = "Copied!";
btn.style.background = "#28a745";
setTimeout(function(){
btn.innerText = originalText;
btn.style.background = "";
}, 2000);
}