Concrete Calculator

Calculate concrete volume, materials needed, and estimated costs for your construction project. Perfect for slabs, footings, walls, driveways, and more.

Measurement Units

Concrete Calculator

Choose your project type and enter dimensions

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Key Features

Multiple project shapes (slabs, footings, walls, stairs)
Imperial and metric unit support
Material estimation for different bag sizes
Cost estimation for ready-mix and bagged concrete

Understanding Concrete

Volume Formula: Length × Width × Thickness
Unit Conversion: 1 cubic yard = 27 cubic feet
Bag Coverage: 40lb=0.30ft³, 60lb=0.45ft³, 80lb=0.60ft³
Waste Factor: 8% included for spillage and variations
Strength: 3000-4000 PSI for residential, 4000+ for commercial

Tips & Strategies

Ready-Mix vs Bags: Use ready-mix for projects >1 cubic yard; bags for small repairs
Thickness Guide: 4" sidewalks, 6" driveways, 8" heavy traffic areas
Waste Factor: Our calculator includes 8% waste for spillage and variations
Delivery Timing: Schedule early morning deliveries for best working conditions
Weather Safety: Avoid pouring below 40°F or above 90°F
Reinforcement: Use rebar for structural elements, fiber mesh for slabs
Cost Optimization: 80lb bags are most economical per cubic foot
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Frequently Asked Questions

How much concrete do I need for a 10x10 slab?

For a 10x10 foot slab that's 4 inches thick, you'll need approximately 1.23 cubic yards (33.3 cubic feet) of concrete.

Should I use ready-mix or bagged concrete?

Ready-mix is more convenient and cost-effective for projects requiring more than 1 cubic yard. Bagged concrete is better for small projects, repairs, or when you need to work in stages.

How accurate are these calculations?

Our calculations provide accurate volume estimates. Always order 5-10% extra to account for waste, spillage, and minor measurement variations.

What's the difference between concrete bag sizes?

40lb bags cover about 0.011 cubic yards, 60lb bags cover 0.017 cubic yards, and 80lb bags cover 0.022 cubic yards. Larger bags are more economical but harder to handle.

What thickness should I use for different projects?

Sidewalks need 4 inches, driveways need 4-6 inches, garage floors need 4-6 inches, and basement floors typically need 4 inches. Check local building codes for footings.

How do I calculate concrete for stairs?

Stair concrete calculation involves the triangular cross-section of the steps. Our calculator uses the formula: (steps × rise × tread ÷ 2) × width. Rise and tread are automatically converted from inches to feet for accurate volume calculation.

Why does the calculator include waste factor?

Our calculator includes an 8% waste factor to account for spillage, measurement variations, and material loss during mixing and pouring. This ensures you order enough concrete for your project.

What's the difference in bag coverage calculations?

We use industry-standard coverage: 40lb bags cover 0.30 cubic feet, 60lb bags cover 0.45 cubic feet, and 80lb bags cover 0.60 cubic feet. This provides more accurate material estimates than simplified ratios.