This calculator helps you determine the volume of topsoil, measured in cubic yards, needed for a specific area of your landscape. Topsoil is the uppermost layer of soil, rich in organic matter and essential for healthy plant growth. Whether you're preparing a garden bed, laying a new lawn, or creating a foundation for landscaping projects, accurately estimating topsoil volume is crucial to avoid under or over-ordering, saving you time and money.
How the Calculation Works
The calculation involves three main steps:
1. Calculate the Volume in Cubic Feet: First, we determine the total volume of the area in cubic feet. This is done by multiplying the length of the area by its width, and then by its depth. Since the depth is usually specified in inches for landscaping projects, we convert inches to feet by dividing by 12 (as there are 12 inches in a foot).
Formula: Volume (cu ft) = Length (ft) × Width (ft) × (Depth (in) / 12)
2. Convert Cubic Feet to Cubic Yards: Topsoil is most commonly sold by the cubic yard. To convert the volume from cubic feet to cubic yards, we divide the total cubic feet by 27, because there are 27 cubic feet in one cubic yard (3 ft × 3 ft × 3 ft = 27 cu ft).
Formula: Volume (cu yd) = Volume (cu ft) / 27
3. Rounding Up: It's always a good practice to round up to the nearest full or half cubic yard to ensure you have enough topsoil and to account for settling or uneven distribution.
Example Calculation
Let's say you need to cover a rectangular garden bed that is 20 feet long and 15 feet wide with a topsoil depth of 4 inches.
Area Length: 20 ft
Area Width: 15 ft
Desired Depth: 4 inches
Step 1: Calculate Volume in Cubic Feet
Volume (cu ft) = 20 ft × 15 ft × (4 in / 12)
Volume (cu ft) = 300 sq ft × 0.3333 ft
Volume (cu ft) ≈ 100 cu ft
Step 2: Convert to Cubic Yards
Volume (cu yd) = 100 cu ft / 27
Volume (cu yd) ≈ 3.70 cubic yards
Step 3: Round Up
For this project, you would order approximately 4 cubic yards of topsoil to be safe.
When to Use This Calculator
Establishing new lawns from seed or sod.
Creating or amending garden beds for vegetables, flowers, or shrubs.
Filling raised garden beds.
Leveling uneven ground.
Top dressing existing lawns to improve soil health.
Always double-check your measurements before calculating. Consider ordering a small percentage extra (5-10%) to account for compaction and settling.
function calculateTopsoil() {
var length = parseFloat(document.getElementById("length").value);
var width = parseFloat(document.getElementById("width").value);
var depthInches = parseFloat(document.getElementById("depth").value);
var resultDiv = document.getElementById("result");
resultDiv.style.display = "block"; // Make sure the result div is visible
if (isNaN(length) || isNaN(width) || isNaN(depthInches) || length <= 0 || width <= 0 || depthInches <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
resultDiv.style.backgroundColor = "#dc3545"; // Red for error
return;
}
// Convert depth from inches to feet
var depthFeet = depthInches / 12;
// Calculate volume in cubic feet
var volumeCubicFeet = length * width * depthFeet;
// Convert volume from cubic feet to cubic yards
var volumeCubicYards = volumeCubicFeet / 27;
// Round up to the nearest convenient unit (e.g., 0.5 or 1 yard for ordering)
// For simplicity, we'll round to two decimal places here, but users should ideally round up.
var roundedVolume = Math.ceil(volumeCubicYards * 2) / 2; // Rounds up to nearest 0.5 cubic yard.
if (roundedVolume < volumeCubicYards) { // If rounding down happened due to .01-.49, add 0.5
roundedVolume += 0.5;
}
if (roundedVolume < 0.5) roundedVolume = 0.5; // Ensure minimum order is at least 0.5 cubic yard if calculation is tiny
resultDiv.innerHTML = roundedVolume.toFixed(1) + " cubic yards (Recommended order, rounded up)";
resultDiv.style.backgroundColor = "var(–success-green)"; // Reset to green for success
}