Countertop Calculator

Countertop estimation involves calculating the total square footage of surface area to be covered, then converting that to material slabs or linear feet depending on the material type. Accurate measurement prevents expensive shortfalls, and that matters most with the premium materials. Quartz and granite have to come from matching slabs, so a shortfall discovered at install is not a trip back to the store. It is a second slab from a different production run, and it will not match.

Total Area formula: Area = Length × Width (per section) Total Area = Σ all sections + Cutout Allowances

Slab Coverage: Slabs Needed = Total Area / Usable Slab Area × Waste Factor

What each variable means:

• Length × Width: measured in inches or centimeters; convert to square feet: divide by 144 (if in inches)
• Overhang: countertops typically overhang the cabinet by 1–1.5 inches; add this to the measured depth
• Cutout Allowances: sinks and cooktops require cutouts; the removed material is waste (you still pay for the full slab)
• Usable Slab Area: standard granite/quartz slabs are typically 55" × 110" (42 sq ft) or 63" × 128" (56 sq ft)
• Waste Factor: 10–15% for simple layouts; 20–25% for L-shapes with seams or veined stone requiring pattern matching

Worked example: Kitchen with three runs of countertop, which is what the three section rows in the calculator are for:

• Run A: 144" × 25.5" (including 1.5" overhang) = 3,672 in²
• Run B: 72" × 25.5" = 1,836 in²
• Island: 60" × 36" = 2,160 in² Total = 7,668 in² ÷ 144 = 53.25 ft² With 20% waste (this kitchen has an island and two seams, so it is not the simple case): 53.25 × 1.20 = 63.9 ft²

At a 55" × 110" slab, usable area is about 42 ft², so this kitchen takes 2 slabs. That is the number that decides the price, not the square footage, because you buy whole slabs and pay for the offcut.

Material price ranges (installed, US, approximate and worth re-checking locally):

• Laminate: $20 to $40/ft² | Butcher block: $35 to $75/ft² | Tile: $25 to $50/ft²
• Granite: $50 to $150/ft² | Quartz: $60 to $150/ft² | Marble: $75 to $200/ft²

Edge treatment, roughly, per linear foot: eased or flat $5 to $10, beveled $8 to $15, bullnose $10 to $20, ogee $15 to $25, waterfall $20 and up. Waterfall is the odd one out because it is not really an edge profile at all. It is a second piece of stone running down the side of the island to the floor, so it eats slab area as well as fabrication time.

Those ranges move every year and vary a lot by region, so treat them as a sanity check on a quote rather than a quote. Put your own numbers in the price fields for the actual arithmetic.

Pro tip: Always add at least 10% waste. Unusual kitchen shapes, angled walls, or veined stone that requires alignment can easily push waste to 20%. Order all material from the same production run to ensure color consistency.