Countertop Square Footage Calculator
Calculate the total square footage of your countertop surfaces. Add multiple sections (e.g., different countertop runs) and include an optional overhang and waste factor for accurate material estimates.
Section 1
Formula
Effective Depth (in) = Depth + Overhang
Section Area (sq in) = Length × Effective Depth
Section Area (sq ft) = Section Area (sq in) ÷ 144
Total Raw Area (sq ft) = Σ Section Areas (sq ft)
Total with Waste (sq ft) = Total Raw Area × (1 + Waste% ÷ 100)
There are 144 square inches in 1 square foot (12 in × 12 in = 144 sq in). The overhang is added to the depth of each section to account for the countertop edge that extends beyond the cabinet.
Assumptions & References
- All measurements are entered in inches and results are returned in square feet.
- A standard countertop depth is 25 inches (24-inch base cabinet + 1-inch overhang), per NKBA (National Kitchen & Bath Association) guidelines.
- The default overhang of 1.5 inches is typical for kitchen countertops; bathroom vanities often use 0.5–1 inch.
- A 10% waste factor is a common industry standard for cuts, seams, and material loss; complex layouts or natural stone may require 15–20%.
- This calculator assumes rectangular countertop sections. Irregular shapes (L-cuts, curves) should be broken into rectangular approximations.
- Results represent the surface area only and do not account for backsplash, edge profiles, or thickness.
- Reference: NKBA Kitchen & Bathroom Planning Guidelines; Marble Institute of America fabrication standards.