Free Concrete Calculator

🧮 Step 1: Enter Your Project Details

Shape:

Length:

ft

Width:

ft

Thickness:

in

Concrete Grade/Strength:

Waste Factor:

Price per Cubic Yard:

$

Calculation Results

Concrete Volume: 1.23 cubic yards

With Waste Factor (10%): 1.35 cubic yards

Estimated Cost: $168.75

Bags of Concrete (60 lb): 55 bags

Bags of Concrete (80 lb): 41 bags

📋 Material Requirements

For a standard concrete mix (1:2:3 ratio), you'll need the following materials per cubic yard:

Material	Quantity	Notes
Portland Cement	6 bags (94 lb each)	Type I or Type II for general construction
Sand (Fine Aggregate)	0.5 cubic yards	Clean, well-graded sand
Gravel (Coarse Aggregate)	0.75 cubic yards	3/4" or 1" stone recommended
Water	33 gallons	Clean, potable water

💡 Pro Tip

For the best results, use a water-to-cement ratio of 0.45 to 0.50 by weight. Too much water weakens concrete, while too little makes it difficult to work with.

Reinforcement Recommendations

Slabs

Use 6x6 W1.4/W1.4 welded wire mesh or #3 rebar in a 16" grid pattern.

Place reinforcement at 1/3 the slab thickness from the top.

Footings

Use #4 rebar in a grid pattern, typically 12" on center.

Place rebar 3" from the bottom and sides of the footing.

Walls

Use vertical #4 rebar 16" on center and horizontal #4 rebar 24" on center.

Ensure 1.5" minimum concrete cover over all reinforcement.

📝 How to Use This Concrete Calculator

Select your preferred unit system (Imperial or Metric)
Choose the shape of your concrete structure (slab, column, etc.)
Enter the dimensions of your project
Select the concrete grade based on your project requirements
Choose a waste factor appropriate for your project complexity
Enter the price per cubic yard of concrete in your area
Click "Calculate" to get your results

The calculator will provide the volume of concrete needed, estimated cost, and material quantities required for your project.

⚠️ Important Note

This calculator provides estimates only. For critical structural applications, always consult with a structural engineer to determine exact requirements.

🔍 Additional Considerations

Concrete Curing Time

Proper curing is essential for concrete strength development:

✓ Initial set: 2-4 hours after pouring
✓ Ready for foot traffic: 24-48 hours
✓ Ready for vehicle traffic: 7-10 days
✓ Full strength: 28 days

Weather Considerations

Temperature affects concrete setting and curing:

✓ Ideal temperature range: 50°F to 85°F (10°C to 29°C)
✓ Hot weather: Use ice water in mix, work quickly, and cure immediately
✓ Cold weather: Use heated water, insulate forms, and protect from freezing

Concrete Mix Additives

Common additives to improve concrete properties:

✓ Air entrainment: Improves freeze-thaw resistance
✓ Water reducers: Improve workability without adding water
✓ Accelerators: Speed up setting time (calcium chloride)
✓ Retarders: Slow setting time for hot weather or complex pours
✓ Fiber reinforcement: Reduces cracking and increases durability

❓ Frequently Asked Questions

How much does a cubic yard of concrete weigh?

A cubic yard of standard concrete weighs approximately 4,000 pounds (2 tons) or 1,800 kilograms. The exact weight can vary based on the mix design and aggregate type.

How many 80 lb bags of concrete make a cubic yard?

It takes approximately 45 bags of 80 lb concrete mix to make one cubic yard. For 60 lb bags, you would need about 60 bags per cubic yard.

What is the minimum thickness for a concrete slab?

For residential applications like patios and walkways, a minimum thickness of 4 inches is recommended. For driveways that will support vehicles, 5-6 inches is recommended. Commercial applications may require 6-8 inches or more.

How long should concrete cure before removing forms?

Wall forms can typically be removed after 24-48 hours. For load-bearing structures, forms should remain in place for at least 7 days. Temperature and concrete mix design can affect these timeframes.

What's the difference between concrete and cement?

Cement is an ingredient in concrete. Concrete is made by mixing cement with sand, gravel, and water. Cement acts as the binding agent that holds the other materials together as it cures.

Do I need to add rebar to my concrete project?

Reinforcement (rebar or wire mesh) is recommended for most concrete projects to prevent cracking and increase strength. Slabs larger than 4x4 feet, footings, walls, and any structural concrete should include reinforcement.

How much does it cost to pour concrete?

The national average cost for concrete is $125-$175 per cubic yard for ready-mix delivered. Additional costs include forms, reinforcement, finishing labor, and site preparation. Small projects may cost more per yard due to minimum delivery charges.