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.
Need a first-pass takeoff draft from your blueprints? Our AI can extract quantities and review flags for estimator verification.
Get Full Takeoff from PlansHow 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
- Measure the length of your concrete area in feet
- Measure the width of your concrete area in feet
- Determine the thickness in inches, then convert to feet (divide by 12)
- Multiply length x width x thickness to get cubic feet
- Divide by 27 to convert cubic feet to cubic yards
- Add 5-10% for waste, spillage, and uneven surfaces
Common Concrete Slab Thicknesses
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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