Standard driveway: 4-6 inches. Heavy duty: 8 inches.
Recommended: 5-10%
How to Calculate Concrete for Your Project
Whether you are pouring a new driveway, a patio, or a foundation slab, estimating the correct amount of concrete is crucial. Ordering too little can result in a "cold joint" and structural weaknesses, while ordering too much is a waste of money.
The Concrete Volume Formula
To determine the volume of concrete needed, you must convert all dimensions to a consistent unit (usually feet) and calculate the cubic footage, which is then converted to Cubic Yards (the standard unit for ordering ready-mix concrete).
For smaller projects, you might use pre-mixed bags (like Quikrete or Sakrete) available at hardware stores. For larger projects (typically over 1-2 cubic yards), ordering a truck is usually more economical and labor-efficient.
80lb Bags: Yield approximately 0.60 cubic feet per bag. You need roughly 45 bags per cubic yard.
60lb Bags: Yield approximately 0.45 cubic feet per bag. You need roughly 60 bags per cubic yard.
Why Add a Waste Margin?
Our calculator allows you to input a waste margin percentage. Professional contractors always order 5% to 10% extra concrete to account for:
Spillage during the pour.
Uneven excavation or subgrade depths.
Settling of forms.
function calculateConcrete() {
// 1. Get Input Values
var length = parseFloat(document.getElementById('cc-length').value);
var width = parseFloat(document.getElementById('cc-width').value);
var thick = parseFloat(document.getElementById('cc-thick').value);
var waste = parseFloat(document.getElementById('cc-waste').value);
// 2. Validate Inputs
if (isNaN(length) || isNaN(width) || isNaN(thick) || length <= 0 || width <= 0 || thick <= 0) {
var resultDiv = document.getElementById('cc-results');
resultDiv.style.display = 'block';
resultDiv.innerHTML = 'Please enter valid dimensions for length, width, and thickness.';
return;
}
if (isNaN(waste) || waste < 0) {
waste = 0;
}
// 3. Calculation Logic
// Convert thickness from inches to feet
var thickInFeet = thick / 12;
// Calculate Cubic Feet (Base)
var cubicFeetBase = length * width * thickInFeet;
// Apply Waste Margin
var wasteMultiplier = 1 + (waste / 100);
var cubicFeetTotal = cubicFeetBase * wasteMultiplier;
// Convert to Cubic Yards (1 Yard = 27 Cubic Feet)
var cubicYardsTotal = cubicFeetTotal / 27;
// Calculate Bags (Standard Yields)
// 80lb bag ~= 0.6 cubic feet
// 60lb bag ~= 0.45 cubic feet
var bags80 = Math.ceil(cubicFeetTotal / 0.60);
var bags60 = Math.ceil(cubicFeetTotal / 0.45);
// 4. Format Results
var resultHtml = '