Free Construction Calculator

Concrete Yards Calculator

Calculate exactly how much concrete you need for your slab, patio, driveway, or foundation. Get results in cubic yards with waste factor included.

Enter Your Dimensions
Input the length, width, and thickness of your concrete pour
Feet
Inches
Your Results
Concrete needed for your project
Cubic Yards Needed
0.00yd3
(0.00 yd3 + waste factor)
60 lb Bags
0
80 lb Bags
0
Cubic Feet
0.00 ft3

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How to Calculate Concrete Yards

Calculating the amount of concrete you need is straightforward once you understand the formula. This guide will walk you through the process step by step.

The Concrete Formula

Cubic Yards = (Length x Width x Thickness) / 27

The number 27 comes from the fact that there are 27 cubic feet in one cubic yard (3 x 3 x 3 = 27). Make sure all your measurements are in feet before using this formula.

Step-by-Step Instructions

  1. Measure the length of your concrete area in feet
  2. Measure the width of your concrete area in feet
  3. Determine the thickness in inches, then convert to feet (divide by 12)
  4. Multiply length x width x thickness to get cubic feet
  5. Divide by 27 to convert cubic feet to cubic yards
  6. Add 5-10% for waste, spillage, and uneven surfaces

Common Concrete Slab Thicknesses

4 inches
Patios, sidewalks, light-duty slabs
5-6 inches
Driveways, garage floors
6-8 inches
Commercial, heavy equipment
8-12 inches
Foundations, structural footings

Why Add a Waste Factor?

Always order more concrete than your exact calculation. Here is why:

  • Uneven ground requires more material to level
  • Spillage during pouring is inevitable
  • Formwork variations may require extra concrete
  • Running short mid-pour creates cold joints and weak spots

Pro Tip

For larger projects, consider getting a professional takeoff from your blueprints. Our AI-powered tool can extract all concrete quantities, rebar requirements, and form dimensions automatically from your PDF plans.

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