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Concrete Slab & Driveway Cost Calculator

Concrete Slab & Driveway Calculator

Current market average is approx. $125 – $150 per yard for ready-mix.
Please enter valid numbers for length, width, and thickness.

Project Estimate

Total Volume Required
0.00 cu. yards
0.00 cu. feet
Estimated Material Cost
$0.00
Excludes labor/reinforcement

Premix Bag Alternative (DIY)

If you are using pre-mixed bags instead of a truck:

  • 80lb Bags needed: 0
  • 60lb Bags needed: 0
function calculateConcrete() { // 1. Get Elements var lenInput = document.getElementById("calc_length"); var widInput = document.getElementById("calc_width"); var thickInput = document.getElementById("calc_thick"); var wasteInput = document.getElementById("calc_waste"); var priceInput = document.getElementById("calc_price"); var resContainer = document.getElementById("calc_results"); var errContainer = document.getElementById("calc_error"); var resYards = document.getElementById("res_yards"); var resFeet = document.getElementById("res_feet"); var resCost = document.getElementById("res_cost"); var resBags80 = document.getElementById("res_bags80"); var resBags60 = document.getElementById("res_bags60"); // 2. Parse Values var L = parseFloat(lenInput.value); var W = parseFloat(widInput.value); var T_in = parseFloat(thickInput.value); var wastePct = parseFloat(wasteInput.value); var pricePerYard = parseFloat(priceInput.value); // 3. Validation if (isNaN(L) || isNaN(W) || isNaN(T_in) || L <= 0 || W <= 0 || T_in <= 0) { errContainer.style.display = "block"; resContainer.style.display = "none"; return; } else { errContainer.style.display = "none"; resContainer.style.display = "block"; } if (isNaN(wastePct)) wastePct = 0; if (isNaN(pricePerYard)) pricePerYard = 0; // 4. Calculation Logic // Convert thickness from inches to feet var T_ft = T_in / 12; // Calculate Cubic Feet var cubicFeet = L * W * T_ft; // Add Waste Factor var totalCubicFeet = cubicFeet * (1 + (wastePct / 100)); // Convert to Cubic Yards (1 Yard = 27 Cubic Feet) var cubicYards = totalCubicFeet / 27; // Calculate Cost var totalCost = cubicYards * pricePerYard; // Calculate Bags (Yield constants: 80lb ~ 0.6 cu ft, 60lb ~ 0.45 cu ft) var bags80 = totalCubicFeet / 0.6; var bags60 = totalCubicFeet / 0.45; // 5. Update DOM resYards.innerHTML = cubicYards.toFixed(2) + ' cu. yards'; resFeet.innerHTML = totalCubicFeet.toFixed(2) + ' cu. feet (incl. ' + wastePct + '% waste)'; // Format currency resCost.innerText = "$" + totalCost.toFixed(2).replace(/\d(?=(\d{3})+\.)/g, '$&,'); // Round bags up to nearest whole number resBags80.innerText = Math.ceil(bags80); resBags60.innerText = Math.ceil(bags60); }

Understanding Concrete Slab Costs

Planning a driveway, patio, or shed foundation requires accurate material estimation to avoid costly overages or project delays. This calculator helps homeowners and contractors determine the exact volume of concrete needed based on standard dimensional measurements.

How to Calculate Concrete Volume

The formula for calculating concrete volume is based on the cubic footage of the area:

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. Additionally, professionals always recommend adding a "waste factor" (typically 5-10%) to account for spillage, uneven subgrades, and form deflection.

Common Concrete Thickness Guidelines

  • 4 Inches: Standard for residential sidewalks, patios, and garage floors for passenger vehicles.
  • 5-6 Inches: Recommended for driveways that host heavier SUVs or trucks, and for hot tub pads.
  • 6+ Inches: Heavy-duty commercial aprons or foundations supporting significant structural weight.

Ready-Mix vs. Pre-Mixed Bags

For small projects (under 1-2 cubic yards), buying 60lb or 80lb bags from a hardware store is often more economical. However, for larger slabs like driveways, ordering a ready-mix truck is standard practice. A single yard of concrete weighs roughly 4,000 lbs, making manual mixing of large volumes extremely labor-intensive.

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