MaterialCalculator
Free Concrete Calculator

Pour your concrete project perfectly.

Whether you are pouring a driveway, patio, or fence post footings, calculate your required volume and get the exact number of premixed bags needed.

Enter Project Dimensions

Project Diagram

L: 10 ftW: 5 ft3 in

Total Volume

Cubic Yards

Enter dimensions above

Estimated Weight

Tons

Based on Concrete density (2 t/yd³)

🛍️

Number of 2 cu ft bags

bags

Recommended Depths for Concrete

Project / Use CaseRecommended Depth
Driveway / Heavy Traffic5–6 inches
Sidewalk / Patio4 inches (standard)
Shed Floor / Base4 inches
Footings / Post Holes12–36 inches

How to Calculate Concrete Volume

Most landscaping suppliers sell concrete by the cubic yard. To convert your project area to cubic yards, use this formula:

Volume (cu yd) = (Length × Width × Depth in feet) ÷ 27

Our calculator also multiplies your cubic yard result by 2 tons/yd³ (the standard density for concrete) to show estimated weight — essential if you are hauling the material yourself or need delivery pricing.

Pro Tips for Concrete Projects

1

A standard 4-inch concrete slab requires gravel sub-base of at least 4 inches and steel mesh or rebar reinforcement for durability.

2

Always add 10% extra concrete to your order to account for spillage, sub-grade unevenness, and forms bowing.

3

Keep concrete moist for at least 3 to 7 days after pouring to ensure it cures to its maximum strength.

Frequently Asked Questions

How many bags of concrete make a cubic yard?
It depends on the bag size. For 80 lb bags, you need 45 bags per cubic yard. For 60 lb bags, you need 60 bags per yard. For 40 lb bags, you need 90 bags per yard.
How deep should a concrete patio slab be?
Standard residential concrete patios, sidewalks, and driveways should be at least 4 inches thick. For heavy-duty use or large trucks, a depth of 5 to 6 inches is recommended.
How long does concrete take to cure?
Concrete technically cures forever, but it reaches about 70% of its full strength after 7 days, and its standard design strength (28-day strength) after 28 days. Avoid driving heavy vehicles on it for at least 7 days.
Can I pour concrete directly on dirt?
You should avoid pouring concrete directly on dirt. It is highly recommended to lay a compacted 4-inch gravel base first. This provides proper drainage and prevents the ground from shifting, which causes cracking.

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