Countertop Square Footage Calculator
Measure each countertop section, then add optional cutouts, backsplash, waste, slabs and costs.
| Item | Area |
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How to measure countertop square footage
- Split the layout into rectangles. For an L-shape, use two rectangles that meet without overlapping.
- Measure each rectangle’s length and front-to-back depth.
- Enter islands, peninsulas and separate runs as additional sections.
- Add backsplash and cutouts only when they are part of the material quote.
- Apply a waste allowance and confirm slab layout with the fabricator.
Checked example: a 120 × 25.5 in run is 3,060 in², or 21.25 sq ft. With 10% waste, the order area is 23.38 sq ft.
Formulas used
Rectangle area = length × depth × quantity. In US units, square inches are divided by 144 to obtain square feet. In metric units, square centimeters are divided by 10,000 to obtain square meters. Net area adds backsplash and subtracts cutouts only when selected. Order area = net area × (1 + waste percentage ÷ 100).
What makes slab count an estimate?
Dividing total area by usable slab area is useful for early planning, but it cannot place seams or rotate pieces around veining, defects, sink rails and required overhangs. A fabricator must make the final cut layout. Do not purchase material from this estimate alone.
Measurement limits
This tool models rectangles. Curves, diagonal corners, waterfall edges, full-height splash, laminated edges and irregular templates require professional measurements. Prices exclude fabrication, cutout labor, delivery, installation, tax and plumbing unless you include them separately in your own quote.