Everyday
Countertop Slab & Cost Calculator
Enter each countertop run as a rectangle, pick a slab size, and the page works out how many slabs you need, where the seams fall, and what each material costs installed.
How it works
Behind the numbers
Most countertop math stops at square footage, which leaves the two expensive questions unanswered: how many slabs to buy and where the seams go. This calculator starts from your layout. Enter each straight run as a rectangle, add an optional 4-inch backsplash, and pick the slab format you are shopping: standard or jumbo quartz, average granite, or a custom size.
Slab count comes from usable area: total square feet times one plus your waste allowance, divided by slab area, rounded up to a whole slab. Seams are estimated per run: any run longer than the slab needs an extra piece, and each inside corner adds one. Slab dimensions shown are common manufacturer formats; your fabricator's actual slabs can differ, so confirm before ordering.
Cost ranges are installed prices per square foot from 2026 buying guides, shown for five material tiers so you can compare laminate against quartz on the same layout. Prices move with slab grade, edge profiles, cutouts, and local labor, so treat the range as a planning number and get a fabricator quote before you commit.
FAQ
Questions, answered
How many slabs do I need for my countertops?
Divide your total countertop square footage, plus a 10–15% cutting-waste allowance, by the usable area of one slab, then round up. A standard quartz slab (120 × 56 in) covers about 46.7 sq ft nominal, so a 60 sq ft kitchen with 15% waste needs 69 ÷ 46.7, which rounds up to 2 slabs.
What is the standard countertop slab size?
There is no single industry standard. Common quartz formats are 120 × 56 in (standard) and 130 × 65 in (jumbo), published by makers like Caesarstone and Cambria; average granite slabs run about 114 × 66 in. Always confirm the exact size with your fabricator, since usable area shrinks after edge trimming.
How much does a countertop cost per square foot installed?
2026 installed ranges from multi-source buying guides: laminate $15–40, butcher block $40–80, granite $40–100, quartz $50–120, marble $75–150. Edge profiles, sink cutouts, and local labor move the final number.
Where will the seams be on my countertop?
Any run longer than the slab needs a seam, and L or U shapes need one at each inside corner. Fabricators usually place seams near sinks or cooktops where they are less visible. The calculator estimates the count; exact placement is a conversation with your fabricator.