How much concrete for a countertop?
Concrete countertop quantity depends on the top footprint and thickness. Estimate each section separately when islands, backsplashes, edge profiles, or returns use different dimensions.
Countertop mix yield matters
Countertop mixes can have different yields from standard concrete bags. Convert the result to cubic feet and compare it with the yield on the specific product label.
Cutouts and edge details
Sink cutouts, faucet holes, thicker edges, forms, reinforcement, pigments, polishing, and sealer are not included in simple volume math.
Common concrete slab sizes
Cubic yards below are before waste. Add your project waste percentage before ordering.
| Slab size | 4 in thick | 5 in thick | 6 in thick |
|---|---|---|---|
| 10 ft x 10 ft | 1.23 cu yd | 1.54 cu yd | 1.85 cu yd |
| 10 ft x 12 ft | 1.48 cu yd | 1.85 cu yd | 2.22 cu yd |
| 12 ft x 12 ft | 1.78 cu yd | 2.22 cu yd | 2.67 cu yd |
| 20 ft x 20 ft | 4.94 cu yd | 6.17 cu yd | 7.41 cu yd |
| 24 ft x 24 ft | 7.11 cu yd | 8.89 cu yd | 10.67 cu yd |
| 30 ft x 40 ft | 14.81 cu yd | 18.52 cu yd | 22.22 cu yd |
Before you calculate
- Measure each countertop section length and width in feet, then enter the planned thickness in inches.
- Calculate islands, backsplashes, and separate pieces independently when thickness or shape changes.
- Treat sink cutouts, edge profiles, reinforcement, and polishing loss as separate planning adjustments.
Common mistakes
- Using cabinet length without measuring the actual countertop footprint.
- Forgetting thicker edges, returns, backsplashes, or multiple sections.
- Assuming countertop mix yield is identical to ordinary concrete bag yield.
Formula
cubic yards = (length * width * (thickness / 12) / 27) * (1 + wastePercent / 100)
Assumptions
- The estimate assumes a rectangular countertop section.
- Thickness is entered in inches.
- Sink cutouts, edge profiles, reinforcement, forms, and polishing loss are not included.
Example
Estimated concrete needed (cubic yards): 0.11 cubic yards
How to use this calculator
- Enter length in ft.
- Enter width in ft.
- Enter thickness in in.
- Enter waste in %.
- Review the live estimate and compare it with the example result.
- Check the formula, assumptions, product labels, and site conditions before using the Concrete Countertop Calculator result to plan materials.
Before you buy materials
- Compare the cubic-foot result with the yield on the countertop mix product label.
- Plan forms, reinforcement, pigment, sealer, and finishing supplies separately from concrete volume.
FAQ
What is the example concrete countertop cubic-yard result?
Use length, width, thickness or depth, and waste, then calculate the planning result. In the default example, the result is 0.11 cubic yards.
How do I calculate concrete for a countertop?
Multiply length by width by thickness in feet. Divide by 27 for cubic yards, or use cubic feet to compare against bag yield.
Should I subtract sink cutouts?
Large cutouts can reduce volume, but many projects still keep a waste buffer for forms, edges, and finishing loss.
Can I use regular concrete bag yield?
Use the yield printed on the countertop mix or concrete product you plan to buy. Product yields can differ.
Does this include reinforcement or sealer?
No. This estimates concrete volume only. Reinforcement, pigments, polishing, and sealer should be planned separately.
Related calculators
This calculator is for planning estimates only. Verify final quantities with product labels, project conditions, and a qualified professional when accuracy matters.