.concrete-calculator-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 0 auto;
color: #333;
line-height: 1.6;
}
.calc-container {
background: #f8f9fa;
border: 1px solid #e9ecef;
border-radius: 8px;
padding: 30px;
margin-bottom: 40px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.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;
font-weight: 600;
margin-bottom: 5px;
font-size: 14px;
color: #495057;
}
.input-group input, .input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ced4da;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 0 3px rgba(0,123,255,0.1);
}
.calc-btn {
background-color: #007bff;
color: white;
border: none;
padding: 12px 24px;
font-size: 18px;
font-weight: bold;
border-radius: 4px;
cursor: pointer;
width: 100%;
margin-top: 10px;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #0056b3;
}
#concreteResult {
margin-top: 25px;
padding: 20px;
background-color: #fff;
border-left: 5px solid #28a745;
display: none;
box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
border-bottom: 1px solid #eee;
padding-bottom: 5px;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
}
.result-label {
font-weight: 500;
}
.result-value {
font-weight: 700;
color: #28a745;
}
.seo-content h2 {
margin-top: 30px;
color: #2c3e50;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.seo-content h3 {
color: #34495e;
margin-top: 25px;
}
.seo-content ul {
padding-left: 20px;
}
.seo-content li {
margin-bottom: 8px;
}
.tip-box {
background-color: #fff3cd;
border: 1px solid #ffeeba;
padding: 15px;
border-radius: 4px;
margin: 20px 0;
font-size: 0.95em;
}
function calculateConcrete() {
// Get input values using var
var len = parseFloat(document.getElementById('slabLength').value);
var wid = parseFloat(document.getElementById('slabWidth').value);
var thick = parseFloat(document.getElementById('slabThickness').value);
var waste = parseFloat(document.getElementById('slabWaste').value);
var cost = parseFloat(document.getElementById('costPerYard').value);
// Validation
if (isNaN(len) || isNaN(wid) || isNaN(thick)) {
alert("Please enter valid numbers for Length, Width, and Thickness.");
return;
}
if (isNaN(waste)) {
waste = 0;
}
// Calculation Logic
// 1. Convert thickness to feet
var thickFt = thick / 12;
// 2. Calculate Cubic Feet
var cubicFeet = len * wid * thickFt;
// 3. Convert to Cubic Yards (27 cubic feet in 1 cubic yard)
var cubicYards = cubicFeet / 27;
// 4. Add Waste %
var totalYards = cubicYards * (1 + (waste / 100));
// 5. Calculate Bags
// Standard yield: 1 cubic yard = approx 45 bags of 80lb mix
// Standard yield: 1 cubic yard = approx 60 bags of 60lb mix
var bags80 = Math.ceil(totalYards * 45);
var bags60 = Math.ceil(totalYards * 60);
// 6. Calculate Cost if provided
var totalCost = 0;
if (!isNaN(cost)) {
totalCost = totalYards * cost;
document.getElementById('costRow').style.display = 'flex';
document.getElementById('resCost').innerText = '$' + totalCost.toFixed(2);
} else {
document.getElementById('costRow').style.display = 'none';
}
// Display Results
document.getElementById('concreteResult').style.display = 'block';
document.getElementById('resYards').innerText = totalYards.toFixed(2) + " Cubic Yards";
document.getElementById('resBags80').innerText = bags80 + " Bags";
document.getElementById('resBags60').innerText = bags60 + " Bags";
}
Concrete Slab Calculator
Calculate cubic yards and premix bags needed for your project.
Calculation Results
Volume Required:
0 Cubic Yards
Pre-Mix Bags (80lb):
0 Bags
Pre-Mix Bags (60lb):
0 Bags
Estimated Material Cost:
$0.00
How to Calculate Concrete for Slabs
Whether you are pouring a driveway, a patio, or a shed foundation, calculating the correct amount of concrete is the most critical step in the planning process. Ordering too little concrete can result in "cold joints" and structural weaknesses, while ordering too much leads to unnecessary waste and disposal costs.
Pro Tip: Always include a safety margin (waste factor) of 5-10% to account for spillage, uneven subgrades, and form deflection.
The Concrete Formula
To determine the volume of concrete needed for a rectangular slab, you must calculate the volume in cubic feet and then convert it to cubic yards, which is the standard unit for concrete delivery.
The formula is:
- Step 1: Convert thickness from inches to feet (Divide inches by 12).
- Step 2: Multiply Length × Width × Thickness (in feet) to get Cubic Feet.
- Step 3: Divide Cubic Feet by 27 to get Cubic Yards.
Common Thickness Guidelines
Selecting the right thickness depends on the intended use of the slab:
- 4 Inches: Standard for residential sidewalks, patios, and garage floors for passenger cars.
- 5-6 Inches: Recommended for driveways holding heavier vehicles, RVs, or light industrial use.
- 6+ Inches: Heavy-duty foundations and commercial applications.
Truck vs. Bagged Concrete
Should you order a ready-mix truck or mix it yourself with bags? Use the calculator above to decide:
- Under 1 Cubic Yard: It is usually more economical to use pre-mixed bags (60lb or 80lb) and rent a small mixer.
- Over 1 Cubic Yard: Ordering from a ready-mix supplier is typically more efficient and ensures a consistent mix for larger pours.