Trench Calculator – Loan calculator

Trench Volume Calculator

Calculate excavation volume and fill material needs

Trench Length (Feet)

Trench Width (Inches)

Trench Depth (Inches)

Waste/Spillage Allowance (%) Standard practice is 5-10% to account for soil expansion or spillage.

Calculation Results:

Cubic Feet: 0 ft³

Cubic Yards: 0 yd³

With Waste: 0 yd³

Total Weight (Est): 0 Tons

*Weight estimation based on standard soil density (approx. 2,500 lbs per cubic yard).

How to Use the Trench Calculator

Planning a utility line, drainage system, or foundation footing requires precise measurements of the earth being moved. This trench calculator helps you determine the exact volume of soil you will excavate or the amount of backfill material (like gravel or sand) you need to order.

The Trench Calculation Formula

To calculate the volume of a trench manually, use the following formula:

            Volume = Length × Width × Depth
        

Because measurements are often taken in different units (Length in feet, Width/Depth in inches), you must convert everything to feet before multiplying:

Width in Feet: Width (inches) / 12
Depth in Feet: Depth (inches) / 12
Cubic Yards: Total Cubic Feet / 27

Real-World Example

Suppose you are digging a trench for a French drain that is 100 feet long, 12 inches wide, and 24 inches deep:

Convert width: 12″ = 1 foot.
Convert depth: 24″ = 2 feet.
Calculate volume: 100′ × 1′ × 2′ = 200 cubic feet.
Convert to yards: 200 / 27 ≈ 7.41 cubic yards.

Important Excavation Considerations

Soil Swell: When soil is excavated, it "swells" or increases in volume because air is introduced. Disturbed soil can take up 15-30% more space than compacted soil. If you are hauling dirt away, always account for this expansion.

Safety First: For any trench deeper than 5 feet, OSHA requires protective systems such as shoring, shielding, or sloping. Always call your local utility location service before you dig to avoid hitting underground power or gas lines.

function calculateTrench() { var length = parseFloat(document.getElementById('trenchLength').value); var widthIn = parseFloat(document.getElementById('trenchWidth').value); var depthIn = parseFloat(document.getElementById('trenchDepth').value); var waste = parseFloat(document.getElementById('wasteFactor').value); if (isNaN(length) || isNaN(widthIn) || isNaN(depthIn)) { alert('Please enter valid numerical values for length, width, and depth.'); return; } // Convert inches to feet var widthFt = widthIn / 12; var depthFt = depthIn / 12; // Calculate Cubic Feet var cubicFeet = length * widthFt * depthFt; // Calculate Cubic Yards var cubicYards = cubicFeet / 27; // Apply Waste factor var wasteMultiplier = 1 + (waste / 100); var totalYardsWithWaste = cubicYards * wasteMultiplier; // Estimate Weight (Avg soil is 2500 lbs per yard, or 1.25 tons) var weightTons = totalYardsWithWaste * 1.25; // Display results document.getElementById('resCubicFeet').innerText = cubicFeet.toFixed(2); document.getElementById('resCubicYards').innerText = cubicYards.toFixed(2); document.getElementById('resWasteYards').innerText = totalYardsWithWaste.toFixed(2); document.getElementById('resWeight').innerText = weightTons.toFixed(2); document.getElementById('trenchResult').style.display = 'block'; }