Kitchen
Interactive Planning StudioCountertop Calculator
Measure perimeter cabinetry runs, kitchen island worktops, and full-height backsplashes to calculate slab yields and fabrication allowances.
Project Parameters
Enter your exact dimensions and specifications
Architectural methodology
About the Countertop Calculator
Natural stone slabs—such as quartzite, Calacatta marble, and soapstone—are sold by the slab rather than the finished piece. Slabs average 120" wide by 55" high (approx. 45 to 55 usable square feet).
Complex L-shaped runs, bookmatched island waterfalls, and sink cutouts generate fabrication offcuts. Calculating true square footage helps stone fabricators confirm slab counts before quarry templating.
Underlying Formula
Total Countertop Square Inches ÷ 144 = Square Feet
Area (sq ft) = (Run 1 Area + Run 2 Area + Island Area) ÷ 144 | Slabs = Ceil(Area ÷ 45)
Step-by-step guidance
How to Use This Tool
Follow these four essential steps to take accurate architectural measurements and prepare your project quantities.
Step 1
Input perimeter counter length (standard depth is 25.5 inches / 65 cm).
Step 2
Add kitchen island dimensions including any seating overhang (typically 12–15 inches).
Step 3
Include backsplash height if running stone up the wall.
Step 4
Review net square footage and estimated slab count.
Expert clarity
Frequently Asked Questions
Common queries answered by our architectural editors and renovation consultants.
What is the standard depth of kitchen countertops?
Standard base cabinets are 24 inches deep. With a 1.5-inch counter overhang, the finished countertop depth is 25.5 inches.
What is a waterfall countertop edge?
A waterfall edge extends the stone vertically down the side of an island to the floor, requiring an additional slab piece matched along the vein.
How many slabs does an average kitchen require?
Most mid-sized kitchens with an island require 2 to 3 full jumbo slabs (approx. 55 sq ft each) to account for seam placement and vein continuity.
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