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Countertop Calculator: Square Feet and Cost
Measure a straight or L-shaped kitchen counter and an island in inches, and get square footage, backsplash area, the number of stone slabs and an installed cost estimate for granite, quartz, laminate or butcher block.
How to measure countertops
Countertops are priced by the square foot, so you need the length and depth of each section in inches. Measure the main run along the back wall from end to end, including the corner. For an L-shape, measure the second run only from where the main run's depth ends, so the corner square is not counted twice. Standard base cabinets are 24 in deep, and the counter overhangs to make it about 25.5 in.
square feet = length (in) × depth (in) ÷ 144
Worked example
An L-shaped kitchen with a 120 in main run and a 60 in second run, both 25.5 in deep, has (120 + 60) × 25.5 ÷ 144 = 31.9 sq ft. A 72 × 36 in island adds 18 sq ft, for 49.9 sq ft of counter. A 4 in backsplash along both walls (120 + 85.5 in) adds 5.7 sq ft. At $60 per sq ft installed, that is about $3,340.
Typical installed prices
| Material | Installed, per sq ft |
|---|---|
| Laminate | $20 to $50 |
| Butcher block | $40 to $100 |
| Granite | $40 to $100 |
| Quartz | $55 to $120 |
| Solid surface | $45 to $95 |
| Marble | $75 to $200 |
Prices vary by region, edge profile and slab grade. Sink and cooktop cutouts, special edges and tear-out of old counters are often charged separately.
How many slabs?
Granite and quartz come in slabs around 120 × 55 in (about 46 sq ft), though jumbo quartz slabs can reach 130 × 65 in. Fabricators lose part of every slab to cuts, seams and veining layout, so the calculator adds 15%. Most fabricators charge for whole slabs, so a 50 sq ft kitchen usually needs two. Ask your fabricator for a layout before you choose the slab.
Tips
- An island seating overhang is usually 10 to 12 in for counter-height stools. Overhangs of more than 10 in on stone need support brackets.
- A full-height backsplash (18 in from counter to upper cabinets) uses far more material than a 4 in splash. Tile is often cheaper there: see our tile calculator.
Frequently asked questions
How do I calculate countertop square footage?
Multiply each section's length by its depth in inches and divide by 144. For an L-shaped counter, measure the second leg from the edge of the first so the corner is counted only once.
How many square feet is an average kitchen countertop?
Most US kitchens have 30 to 50 sq ft of countertop, plus 15 to 20 sq ft with an island.
What is the standard countertop depth?
Kitchen counters are usually 25 to 25.5 in deep, which overhangs a 24 in base cabinet by about 1 to 1.5 in. Bathroom vanity tops are about 22 in deep.