.calc-header {
text-align: center;
margin-bottom: 30px;
}
.calc-header h2 {
margin: 0;
color: #2c3e50;
font-size: 28px;
}
.calc-header p {
color: #7f8c8d;
margin-top: 5px;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.calc-grid {
grid-template-columns: 1fr;
}
}
.input-group {
margin-bottom: 15px;
}
.input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #34495e;
}
.input-group input {
width: 100%;
padding: 10px;
border: 1px solid #bdc3c7;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #3498db;
outline: none;
box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}
.calc-btn {
grid-column: 1 / -1;
background-color: #e67e22;
color: white;
padding: 15px;
border: none;
border-radius: 4px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s;
width: 100%;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #d35400;
}
#concrete-results {
margin-top: 30px;
padding: 20px;
background-color: #fff;
border: 1px solid #dcdcdc;
border-left: 5px solid #27ae60;
border-radius: 4px;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.result-row:last-child {
border-bottom: none;
}
.result-label {
color: #7f8c8d;
font-weight: 500;
}
.result-value {
color: #2c3e50;
font-weight: 800;
font-size: 18px;
}
.article-content {
margin-top: 50px;
line-height: 1.6;
color: #444;
}
.article-content h3 {
color: #2c3e50;
margin-top: 25px;
}
.waste-note {
font-size: 12px;
color: #e74c3c;
margin-top: 5px;
}
Estimation Results (Includes Waste)
Total Volume (Cubic Yards):
–
Total Volume (Cubic Feet):
–
Est. Truck Delivery Cost:
–
DIY Pre-Mixed Bags Needed
80lb Bags Required:
–
60lb Bags Required:
–
Est. Cost (Using 80lb Bags):
–
function calculateConcrete() {
// 1. Get Input Values
var length = parseFloat(document.getElementById('slabLength').value);
var width = parseFloat(document.getElementById('slabWidth').value);
var thick = parseFloat(document.getElementById('slabThickness').value);
var waste = parseFloat(document.getElementById('wasteFactor').value);
var priceYard = parseFloat(document.getElementById('pricePerYard').value);
var priceBag = parseFloat(document.getElementById('pricePerBag').value);
// 2. Validate Inputs
if (isNaN(length) || length <= 0 || isNaN(width) || width <= 0 || isNaN(thick) || thick 0) {
truckCost = totalCuYards * priceYard;
truckCostStr = "$" + truckCost.toFixed(2);
}
if (!isNaN(priceBag) && priceBag > 0) {
bagCost = bags80 * priceBag;
bagCostStr = "$" + bagCost.toFixed(2);
}
// 4. Update DOM
document.getElementById('resYards').innerHTML = totalCuYards.toFixed(2) + " yd³";
document.getElementById('resFeet').innerHTML = totalCuFt.toFixed(2) + " ft³";
document.getElementById('resTruckCost').innerHTML = truckCostStr;
document.getElementById('resBags80').innerHTML = bags80 + " bags";
document.getElementById('resBags60').innerHTML = bags60 + " bags";
document.getElementById('resBagCost').innerHTML = bagCostStr;
// Show Results Container
document.getElementById('concrete-results').style.display = 'block';
}
How to Calculate Concrete for Your Slab
Whether you are pouring a patio, a driveway, or a shed foundation, accurately estimating the amount of concrete you need is crucial. Ordering too little leads to expensive delays and "cold joints," while ordering too much is a waste of money.
The Concrete Volume Formula
To find the volume of your slab, use the standard geometric formula for volume:
Length (ft) × Width (ft) × Thickness (ft) = Cubic Feet
Since concrete is typically sold by the Cubic Yard, you must divide the total cubic feet by 27 (since there are 27 cubic feet in one cubic yard).
Why Include a Waste Margin?
This calculator includes a "Waste Margin" input (default set to 10%). It is industry standard to order 5-10% more concrete than the exact mathematical volume. This accounts for:
- Spillage during the pour.
- Uneven subgrade (ground) depth.
- Settling of the forms.
- Concrete remaining in the pump or mixer.
Choosing the Right Thickness
The thickness of your slab depends on its intended use:
- 4 Inches: Standard for walkways, patios, and shed bases.
- 5-6 Inches: Recommended for driveways accommodating passenger vehicles.
- 6+ Inches: Necessary for heavy machinery or RV pads.
Bags vs. Ready-Mix Truck
If your project requires less than 1 cubic yard (approx. 45-50 bags of 80lb mix), mixing it yourself is often more economical. For projects exceeding 2 cubic yards, ordering a ready-mix truck is usually the better option to ensure a consistent cure and save physical labor.