Concrete Countertop Calculator
Calculate concrete for DIY countertops. Enter length, width and thickness in inches to get exact cubic feet and bags needed.
Countertop Dimensions
Concrete Required
How to Calculate Concrete for Countertops
When planning a concrete countertop, precision is key. Because countertops are much smaller than floor slabs, the measurements are typically taken entirely in inches. First, measure the inside dimensions of your melamine form or mold (length and width).
Multiply the length by the width to get square inches, then multiply that by your desired thickness to get total cubic inches. Finally, divide by 1,728 to convert cubic inches into cubic feet. Most specialized high-strength countertop mixes are sold in 50lb bags, which yield roughly 0.37 cubic feet each.
Countertop Calculation Formula
Cubic Feet = (Length in inches × Width in inches × Thickness in inches) ÷ 1,728
Example for a 72-inch long, 25-inch wide countertop poured at 2 inches thick: (72 × 25 × 2) ÷ 1,728 = 2.08 cubic feet.
Frequently Asked Questions
How many bags of concrete for a countertop?
It depends on the size. For a standard 24-inch wide by 72-inch long countertop poured at 2 inches thick, you will need exactly two cubic feet of concrete, which requires about six 50lb bags of countertop mix.
How thick should a concrete countertop be?
A standard concrete countertop should be 1.5 to 2 inches thick. If you plan to make it thicker than 2 inches, you should strongly consider using a foam core to reduce the final weight of the piece.
Can I use standard concrete for countertops?
While you can use a high-strength standard 5000 PSI concrete mix (like Quikrete 5000), it is highly recommended to use a specialized countertop mix. Countertop mixes lack large gravel aggregates, resulting in a much smoother, pinhole-free finish.
How heavy is a concrete countertop?
Solid concrete is very heavy. A standard 2-inch thick concrete countertop weighs approximately 22 to 24 pounds per square foot. A 2x6 foot piece will weigh over 270 pounds.