Countertop Calculator
Measure each counter run separately, enter its length and depth in feet, and get the total square footage fabricators use to quote granite, quartz, or laminate.
Total area: 100.0 sq ft
How it works
Break the countertop into straight rectangular runs and enter each as its own area. A typical L-shaped kitchen is two runs and a U-shape is three; use the Add area button for up to five.
Depth is entered in feet, not inches. A standard run over 24-inch base cabinets finishes 25 inches deep once the overhang is included, which is 2.08 ft. The chart below converts the other common depths.
Where two runs meet at a corner, measure the first run wall to wall and start the second at the edge of the first, so the corner square is not counted twice.
Reference chart
Countertop depth in inches converted to feet
| Countertop type | Typical depth | Depth in feet |
|---|---|---|
| Standard run over base cabinets | 25 in | 2.08 |
| Cabinet box only, no overhang | 24 in | 2.00 |
| Deep custom run | 26 in | 2.17 |
| Raised bar or ledge | 12 in | 1.00 |
| Kitchen island, no seating | 36 in | 3.00 |
| Island with seating overhang | 42 in | 3.50 |
| Bathroom vanity | 22 in | 1.83 |
How to measure an L-shaped or U-shaped countertop
Countertops are almost never one rectangle. Treat every straight run as its own area: a galley kitchen is two runs, an L-shape is two, and a U-shape is three. Enter each run's length along the wall and its finished depth, and the calculator adds them up.
The corner is where most estimates go wrong. If two runs meet at a right angle, the corner square belongs to one run only. Measure the first run the full distance wall to wall, then start the second run at the front edge of the first. Counting it twice on a 25-inch counter adds about 4.3 sq ft that does not exist.
Islands and peninsulas are separate areas, not part of a wall run. So are raised bar ledges, which are usually shallower than the counter they sit behind. Measure a vanity the same way, using its own depth rather than the kitchen figure.
Countertop cost per square foot by material
Fabricators quote slab countertops per square foot installed, which normally bundles the slab, fabrication, edge profile, cutouts and installation. Multiply your total square footage by a figure from the range below to get a realistic budget before you call anyone.
These are national US ranges for 2026 and they are wide on purpose. Where you land depends on your region, the grade of the slab, how elaborate the edge profile is, how many cutouts and seams the layout needs, and whether the old counter has to be torn out. Treat the low end as a builder-grade job and the high end as a premium stone with detailed edge work, then get three local quotes.
Installed countertop cost per square foot (2026 US national ranges)
| Material | Installed cost per sq ft | What drives the range |
|---|---|---|
| Laminate | $20 – $50 | Edge profile; seams stay visible |
| Butcher block | $40 – $100 | Wood species; needs periodic oiling |
| Tile | $30 – $90 | Tile choice; grout lines need sealing |
| Granite | $50 – $200 | Rarity of the stone; slab grade |
| Quartz (engineered) | $60 – $150 | Brand and pattern; no sealing needed |
| Marble | $75 – $250 | Stone grade; etches on contact with acids |
Slabs, seams, and waste
Granite, quartz and marble are sold as whole slabs, so your square footage has to be mapped onto slab-sized pieces. Slabs are not sold by the square foot off the rack: if a 40 sq ft kitchen will not nest inside one slab, you buy two and pay for the offcut.
Usable yield runs roughly 70 to 80 percent of a slab's gross area. The loss comes from cutouts, the strips trimmed off to square the edges, seam allowances, and — on veined stone — the material sacrificed to keep the pattern running across a seam. Divide your total by 70 to 80 percent of the gross area below and round up to whole slabs.
Do not subtract sink and cooktop cutouts from your square footage. Fabricators price the full counter footprint because they still buy, cut and dispose of that material; most shops add a flat fee per cutout on top. Backsplash is the opposite case — it is normally quoted separately by the linear foot, so keep it out of your counter total.
Common slab sizes and gross area
| Material | Typical slab size | Gross area |
|---|---|---|
| Granite, standard | 105 × 54 in | 39 sq ft |
| Granite, jumbo | 120 × 78 in | 65 sq ft |
| Quartz, standard | 120 × 55 in | 46 sq ft |
| Quartz, jumbo | 126 × 63 in | 55 sq ft |
| Marble, standard | 110 × 65 in | 50 sq ft |
Frequently asked questions
How many square feet is a typical kitchen countertop?
Most kitchens run about 30 to 40 sq ft of perimeter counter. Adding a 3 ft × 6 ft island brings the total closer to 50 sq ft. Those are averages only — layouts vary far more than the averages suggest, so measure your own runs.
What countertop depth should I enter, 24 or 25 inches?
Use 25 in (2.08 ft) for a standard run. Base cabinets are 24 in deep and the countertop overhangs the door fronts by about an inch. Enter 24 in only when the slab is being cut flush to the cabinet box with no overhang.
Should countertops be measured in linear feet or square feet?
Fabricators quote the counter itself per square foot, but sell edge work and backsplash per linear foot. To convert, multiply linear feet by the depth in feet: 12 linear ft at 25 in deep is 12 × 2.08 = 25 sq ft.
How much waste should I add for countertop cutouts and seams?
Allow 10 to 15 percent on top of your measured area when estimating how much slab to buy. Do not deduct sink or cooktop openings from the square footage — the fabricator still purchases and cuts that material, and usually charges a separate fee per cutout.
How many slabs of granite or quartz will my kitchen need?
Divide your total square footage by roughly 70 to 80 percent of the slab's gross area, then round up to whole slabs. A 46 sq ft quartz slab yields about 32 to 37 usable sq ft, so a 40 sq ft kitchen normally takes two slabs.
Does the backsplash count in countertop square footage?
No. A 4-inch stone backsplash is normally quoted by the linear foot, and a full-height backsplash is priced as its own square footage. Keep both out of your counter total and ask for the backsplash as a separate line item.
Link to this calculator
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<a href="https://diymaterialcalculators.com/countertop/">Countertop Calculator</a> — free online calculator