Concrete Mix Calculator

The Concrete Mix Calculator estimates how much material you need for a concrete pour — whether you're laying a slab, footing, or pathway. Enter your project's length, width, and depth/thickness, then select your mix ratio (from light-duty 1:5:10 to high-strength 1:1.5:3) and a waste factor to get your total concrete volume plus exact quantities of cement, sand, and gravel needed, including a cement bag count based on standard 94 lb bags.

ft
ft
inches
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Account for spillage and waste

Results

Total Concrete Volume

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Cement Needed

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Sand Needed

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Gravel Needed

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Cement Bags (94 lb)

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Frequently Asked Questions

What do the concrete mix ratios mean?

Mix ratios show the proportion of cement:sand:gravel by volume. For example, 1:3:6 means 1 part cement, 3 parts sand, and 6 parts gravel. Higher cement ratios create stronger concrete but cost more.

How much concrete do I need for a standard slab?

For a 4-inch thick slab, you need about 0.012 cubic yards per square foot. A 10x10 foot area (100 sq ft) would require approximately 1.2 cubic yards of concrete.

Should I add extra concrete for waste?

Yes, always order 5-10% extra concrete to account for spillage, uneven surfaces, and measurement variations. It's better to have slightly too much than to run short during a pour.

What's the difference between wet and dry volume?

Wet volume is the final concrete volume after mixing. Dry volume is about 54% larger because the materials compact when mixed with water. Our calculator accounts for this automatically.

How many bags of cement do I need?

A standard 94-pound bag of Portland cement contains approximately 1 cubic foot of material. The calculator converts cubic yard requirements to bag quantities for easy purchasing.

Can I use this calculator for footings and walls?

Yes, this calculator works for any rectangular concrete project including slabs, footings, walls, and sidewalks. Just enter the length, width, and thickness dimensions.

What mix ratio should I use for my project?

Use 1:5:10 for light-duty projects, 1:3:6 for standard slabs and walkways, 1:2:4 for driveways and heavy-duty applications, and 1:1.5:3 for high-strength structural work.

How do I convert between different measurement units?

The calculator uses feet for length/width and inches for depth by default. Results are shown in cubic yards, which is the standard unit for ordering concrete from suppliers.