Free estimate — verify against local code before building
Countertop Calculator
Measure each run to estimate countertop square footage, backsplash, whole stone slabs, and editable material cost.
What this calculator includes
Enter each countertop run as a length and depth — up to four segments for L-shapes, U-shapes, and an island. The calculator converts runs to square feet, adds an optional backsplash along the full run length, applies an editable waste/seam allowance, and prices the total with editable materials-only rates for laminate, butcher block, solid surface, quartz, and granite. Quartz and granite also get a planning slab count, and the live diagram redraws your layout to scale.
How to use this countertop calculator
- 01
Measure each run
Measure every countertop section along the wall in inches, then measure its depth front to back. Standard depth is 25.5 inches over 24-inch base cabinets; islands often run 38–42 inches deep.
- 02
Add the backsplash
A standard 4-inch backsplash runs along the full length of every wall segment. Enter a different height for a taller splash, or turn it off if you are tiling the wall instead.
- 03
Set the waste and seam allowance
Ten percent covers cutting, seams, and edge finishing on most jobs. Use 15% for stone with strong movement or veining, where matching patterns across seams wastes more of each slab.
- 04
Pick a material and check the cost
The $/sq ft rates are editable materials-only planning numbers. Template, fabrication, edge work, delivery, and installation are not included, so get fabricator quotes before budgeting.
Calculation sources and review
Primary references and formula assumptions are linked so you can verify them against the selected product, supplier, and adopted local requirements.
Internal formula review completed July 13, 2026. What this review covers
- Lowe's — countertop buying guide (opens in a new tab)
Material comparisons and standard depth guidance; product pricing still controls.
- Natural Stone Institute — consumer resources (opens in a new tab)
Industry standards for natural-stone fabrication, seams, and slab yield.
- MSI Surfaces — quartz and natural stone slabs (opens in a new tab)
Typical slab dimensions behind the 55 × 120 in planning yield.
Frequently asked questions
How do I calculate countertop square footage?
Measure each run's length and depth in inches, multiply them, and divide by 144 to get square feet. Add the runs together, add the backsplash (length × height ÷ 144), then add a 10–15% waste and seam allowance.
What is the standard countertop depth?
Standard countertops are 25.5 inches deep — a 24-inch base cabinet plus a 1.5-inch overhang. Islands are commonly 38–42 inches deep when they include seating, and bar tops vary widely.
How many square feet are in a quartz or granite slab?
Nominal slabs are roughly 55–65 inches by 115–130 inches. This calculator plans on about 45.8 usable square feet per slab (55 × 120 in), but layout, seams, and vein matching decide the real yield — your fabricator confirms the count.
Do sink and cooktop cutouts reduce the material I need?
No. Cutouts get no area credit because the offcut in the middle of a run is almost never usable elsewhere. You still pay for the full rectangle each piece is cut from.
Does this countertop estimate include fabrication and installation?
No. The editable rate is a materials-only planning input. Template, fabrication, edge profiles, cutouts, delivery, and installation vary by layout and fabricator, so collect project-specific quotes for the full price.