Countertop Calculator: How Much Countertop Do I Need?
Enter each counter run by its length and depth. You will get the surface area, the backsplash separately, and a rough slab count — the figure a fabricator quotes against is the fabricated area including waste, so that is what this shows.
Counter runs
Measure each run along the wall, including the overhang past the cabinets.
The slab count is a rough planning figure. Real slabs vary from about 45 to 70 sq ft, are rarely clean rectangles, and how many runs fit on one depends on their shape and the direction of the veining. A fabricator’s template beats any calculator here.
How much countertop do I need?
Measure each run along the wall and multiply by its depth. Counters are quoted in square feet of fabricated material, so waste for seams, cutouts and slab layout is part of what you pay for rather than something you can avoid.
The backsplash is kept separate because it is fabricated and often priced differently — sometimes from offcuts of the same slab, sometimes as a separate item, sometimes not in stone at all.
Counter depths
| Depth | Typical of |
|---|---|
| 25.5 in | Standard base cabinets with overhang |
| 28 in | Deeper runs and peninsulas |
| 36 in | Islands with seating overhang |
Standard base cabinets are 24 inches deep and the counter overhangs by an inch or so, which is where 25.5 comes from. An island with seating on one side is deeper again.
Why the slab count is only a guess
A slab is not a rectangle you can fill neatly. It has natural edges, its veining runs one way, and a fabricator laying out an L-shaped kitchen has to place each piece so the pattern continues across a seam. Two kitchens with identical square footage can need different numbers of slabs.
Use the figure here to know roughly what you are dealing with — one slab or three — and to sanity-check a quote. For the actual order, the fabricator templates the kitchen.
How to measure
An L-shaped kitchen is two runs; an island is a third. They may not share a depth.
Not the cabinet run underneath.
A wall run usually does; an island usually does not.
Common mistakes
- Measuring the cabinet run instead of the counter with its overhang.
- Adding a backsplash to an island that does not touch a wall.
- Treating the slab count as an order rather than a rough guide.
- Forgetting that fabrication waste is material you pay for.
Tiling the backsplash instead?
Work out the tile for the wall behind the counter.
Open the Tile Calculator →