.calculator-container {
max-width: 800px;
margin: 0 auto;
font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
color: #333;
line-height: 1.6;
}
.calc-box {
background-color: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
margin-bottom: 40px;
}
.calc-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.input-group {
margin-bottom: 20px;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #495057;
}
.input-row {
display: flex;
gap: 20px;
flex-wrap: wrap;
}
.col-half {
flex: 1;
min-width: 200px;
}
.calc-input {
width: 100%;
padding: 12px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
transition: border-color 0.2s;
box-sizing: border-box;
}
.calc-input:focus {
border-color: #007bff;
outline: none;
}
.btn-calc {
display: block;
width: 100%;
background-color: #d35400; /* Concrete orange/brown theme */
color: white;
border: none;
padding: 15px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 10px;
}
.btn-calc:hover {
background-color: #a04000;
}
#calc-results {
margin-top: 30px;
padding-top: 20px;
border-top: 2px solid #dee2e6;
display: none;
}
.result-card {
background: #fff;
padding: 15px;
border-radius: 6px;
border-left: 5px solid #d35400;
margin-bottom: 15px;
box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.result-label {
font-size: 14px;
color: #6c757d;
text-transform: uppercase;
letter-spacing: 0.5px;
}
.result-value {
font-size: 28px;
font-weight: 700;
color: #212529;
}
.result-sub {
font-size: 14px;
color: #666;
margin-top: 5px;
}
.article-content h2 {
color: #2c3e50;
border-bottom: 2px solid #d35400;
padding-bottom: 10px;
margin-top: 40px;
}
.article-content h3 {
color: #4a5568;
margin-top: 25px;
}
.article-content p {
margin-bottom: 15px;
}
.article-content ul {
margin-bottom: 20px;
padding-left: 20px;
}
.article-content li {
margin-bottom: 8px;
}
.error-msg {
color: #dc3545;
text-align: center;
margin-top: 10px;
display: none;
font-weight: 600;
}
function calculateConcrete() {
// Get input elements matches EXACTLY to HTML IDs
var lengthInput = document.getElementById("slabLength");
var widthInput = document.getElementById("slabWidth");
var thicknessInput = document.getElementById("slabThickness");
var wasteInput = document.getElementById("wasteFactor");
var priceInput = document.getElementById("pricePerYard");
// Output elements
var resultDiv = document.getElementById("calc-results");
var errorDiv = document.getElementById("errorMsg");
var resYards = document.getElementById("resYards");
var resBags80 = document.getElementById("resBags80");
var resBags60 = document.getElementById("resBags60");
var resCost = document.getElementById("resCost");
var costCard = document.getElementById("costCard");
// Parse values
var len = parseFloat(lengthInput.value);
var wid = parseFloat(widthInput.value);
var thick = parseFloat(thicknessInput.value);
var waste = parseFloat(wasteInput.value) || 0;
var price = parseFloat(priceInput.value) || 0;
// Validation
if (isNaN(len) || isNaN(wid) || isNaN(thick) || len <= 0 || wid <= 0 || thick 0) {
costCard.style.display = "block";
resCost.innerHTML = "$" + totalCost.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,');
} else {
costCard.style.display = "none";
}
resultDiv.style.display = "block";
}
How to Calculate Concrete for Your Project
Planning a patio, driveway, or shed foundation requires accurate measurements to ensure you order enough concrete without overspending. This Concrete Slab Calculator helps you determine the exact volume needed in cubic yards, as well as the equivalent number of pre-mix bags for smaller DIY projects.
The Formula for Concrete Volume
Concrete is measured by volume, specifically in Cubic Yards. The basic formula to calculate the volume of a rectangular slab is:
Length (ft) × Width (ft) × Thickness (ft) = Cubic Feet
Since most thickness measurements are in inches, you must first divide the inches by 12 to convert them to feet. Finally, divide the total Cubic Feet by 27 to get Cubic Yards.
Cubic Yards vs. Pre-Mix Bags
Should you order a ready-mix truck or buy bags? This largely depends on the size of your project:
- Large Projects (> 1 yard): If your calculator result is over 1 to 1.5 cubic yards, it is usually more cost-effective and physically manageable to order ready-mix concrete delivered by a truck.
- Small Projects (< 1 yard): For walkways, small pads, or setting posts, buying 60lb or 80lb bags of pre-mix (like Quikrete or Sakrete) is standard.
Yield Reference: An 80lb bag typically yields about 0.60 cubic feet of cured concrete, while a 60lb bag yields about 0.45 cubic feet.
The Importance of Waste Margin
Professional contractors never order the exact mathematical amount of concrete. Uneven subgrades, spilling, and form spreading can absorb more material than expected. It is industry standard to add a 5% to 10% safety margin (waste factor) to your calculation. Running out of concrete in the middle of a pour is a disaster you want to avoid!
Standard Slab Thicknesses
- 4 Inches: Standard for sidewalks, patios, and residential garage floors.
- 5-6 Inches: Recommended for driveways that hold heavier vehicles or light trucks.
- 6+ Inches: Heavy-duty applications, agricultural slabs, or areas with poor soil conditions.