Concrete Countertop Calculator

Calculator built by BuilderToolkits | Updated February 2026

Estimate concrete countertop volume using length, width, thickness, and section count. This concrete countertop calculator includes edge thickening and sink cutout deductions, then returns cubic yards, cubic feet, and 80‑lb bag counts for planning. For reinforcement and subbase planning, use the concrete slab calculator, the rebar estimator and the gravel base calculator.

Inputs

Adds a 1-inch edge band around the perimeter.

Subtracts cutout area from the slab volume.

Results

Concrete volume
0.14 yd³
3.67 ft³ total
Includes 10% waste.
80-lb bags (rough)
7 bags
Assumes ~0.6 ft³ yield per 80-lb bag (varies by mix).

Assumptions

  • Countertops are flat slabs with uniform thickness.
  • Edge thickening uses a 1-inch (25 mm) perimeter band.
  • Waste factor covers spillage, forms, and finish loss.

Next Steps

Round up to the nearest 0.25 yd³ for ready-mix orders.
Estimate reinforcement with the rebar estimator.
For mix planning, use the concrete bag calculator.

Example

A 8 ft × 2.5 ft countertop at 2 in thickness with 1 section(s) needs about 0.14 yd³ of concrete.

How to Calculate a Concrete Countertop (Formula)

Base volume (ft³): (Length × Width − Cutout Area) × Thickness

Edge thickening (ft³): Perimeter × Edge Band Width × Extra Thickness

Cubic yards: (Base + Edge) ÷ 27 × (1 + Waste %)

FAQ

How thick should concrete countertop be?

Many concrete countertops are 1.5–2 inches thick with edge thickening for a heavier look. Thickness depends on design, reinforcement, and handling.

How heavy is concrete countertop?

Concrete weighs roughly 145–150 lb per cubic foot. A 2-inch slab is about 24–25 lb per square foot before edge thickening.

Do I need reinforcement?

Yes. Most countertops use rebar, welded wire, or fiberglass mesh to control cracking. Use the rebar estimator for planning and verify design requirements.

How long to cure?

Concrete countertops typically cure for 7–28 days depending on mix and sealer schedule. Follow the product and sealer manufacturer guidelines.

How much does concrete countertop cost?

Costs vary by mix, finish, and fabrication. DIY materials are often cheaper, while custom installs can be premium. Use your volume to estimate mix and sealer costs, and plan bag quantities with the concrete bag calculator.

Concrete Estimating Guide