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Concrete Calculator

Calculate concrete volume, weight, and material requirements for your construction projects. Perfect for contractors, builders, and DIY enthusiasts.

Project Details

Dimensions

0%10%20%

Concrete Requirements

2.96
Cubic Yards
3.26 yd³ (with 10% waste)
80.0
Cubic Feet
12000
Pounds

Material Requirements

Ready-Mix Concrete

Volume needed: 3.26 yd³
Truck loads: 1
(10 yd³ per truck)

Concrete Bags

80 lb bags: 134
60 lb bags: 178
For smaller projects

Estimated Costs

Ready-Mix Concrete
$407
$100-150/yd³
Bagged Concrete
$670
$4-6/bag
Labor (Optional)
$1200
$3-8/sq ft

Project Summary

Project Type: Concrete Slab
Dimensions: 20 × 12 ft, 4 in thick
Surface Area: 240.0 sq ft
Concrete Strength: 3000-4000 PSI (recommended)
Curing Time: 28 days for full strength

How to Use

1

Select your project type (slab, footing, wall, column, etc.) and unit system.

2

Enter the dimensions of your concrete project accurately.

3

Adjust the waste factor based on your project complexity (5-15% typical).

4

Review the volume, weight, material requirements, and cost estimates.

Understanding Concrete

Concrete Basics

Composition

  • • Cement: 10-15% (binding agent)
  • • Water: 15-20% (activates cement)
  • • Aggregates: 65-75% (sand & gravel)
  • • Air: 1-3% (workability)

Properties

  • • Density: ~150 lb/ft³ (2400 kg/m³)
  • • Compressive strength: 3000-5000 PSI
  • • Working time: 30-60 minutes
  • • Initial set: 2-4 hours

Concrete Strength

2500 PSI

Residential footings, basement walls

3000 PSI

Driveways, slabs, sidewalks

4000+ PSI

Commercial, heavy-duty applications

Ordering Tips

Ready-Mix: Best for large projects (>1 yd³). Order 5-10% extra for waste.
Bagged Mix: Convenient for small projects (<1 yd³). More expensive per volume.
Timing: Have all prep work done. Concrete trucks wait time is limited.

Applications

Residential

  • • Driveways and walkways
  • • Patio slabs
  • • Foundation footings
  • • Basement floors
  • • Retaining walls

Commercial

  • • Building foundations
  • • Parking lots
  • • Warehouse floors
  • • Structural columns
  • • Loading docks

Infrastructure

  • • Road construction
  • • Bridge foundations
  • • Culverts and drainage
  • • Airport runways
  • • Dam construction

Example Calculations

Example 1: Driveway Slab

Dimensions: 20 ft × 12 ft × 4 inches thick
Waste factor: 10%
Volume = 20 × 12 × (4/12) ÷ 27 = 2.96 cubic yards
With waste = 2.96 × 1.10 = 3.26 cubic yards

Example 2: Foundation Footing

Dimensions: 40 ft × 2 ft × 1 ft deep
Waste factor: 15%
Volume = 40 × 2 × 1 ÷ 27 = 2.96 cubic yards
With waste = 2.96 × 1.15 = 3.41 cubic yards

Example 3: Circular Column

Dimensions: 12 inch diameter × 8 ft height
Waste factor: 5%
Volume = π × (0.5)² × 8 ÷ 27 = 0.23 cubic yards
With waste = 0.23 × 1.05 = 0.24 cubic yards

Frequently Asked Questions

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

For a 10×10 ft slab that's 4 inches thick, you need about 1.23 cubic yards of concrete. With 10% waste factor, order 1.35 cubic yards.

Should I use ready-mix or bagged concrete?

Ready-mix is more economical for projects over 1 cubic yard. Bagged concrete is convenient for smaller projects but costs 2-3 times more per cubic yard.

How long does concrete take to cure?

Concrete reaches about 70% strength in 7 days and full strength in 28 days. You can typically walk on it after 24-48 hours and drive on it after 7 days.

What's the difference between cement and concrete?

Cement is just one ingredient in concrete. Concrete is the mixture of cement, water, sand, and gravel. Cement acts as the binding agent that holds everything together.

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