An L-shaped kitchen with runs of 10 and 8 feet at the standard 25½ in depth has 33.7 square feet of countertop — not 38, because the corner square is counted twice when both runs are measured along the walls. With a 4 in backsplash and a sink and cooktop it fits on one jumbo quartz slab; add a 6 × 3 ft island and it takes two. The calculator above works this out for straight, L, U and galley kitchens.
How the calculator works
Choose the layout and measure each run along the wall, then the depth, the exposed ends, the backsplash height and an island if there is one. Pick the material — laminate, granite, quartz or butcher block — and the cutouts. The result is the square footage, the finished edge, the backsplash, the slabs or laminate lengths and the seams.
Corners
Measuring every run along its wall is the easiest way, but where two runs meet in an inside corner the square depth × depth belongs to both. Subtract it once per corner: an L has one, a U two. A galley has none — its two runs face each other.
| Kitchen at 25½ in | Runs | Countertop |
|---|---|---|
| Straight | 10 ft | 21.3 ft² |
| L-shaped | 10 + 8 ft | 33.7 ft² |
| U-shaped | 8 + 10 + 8 ft | 46.2 ft² |
| Galley | 10 + 10 ft | 42.5 ft² |
Edge, backsplash and cutouts
Fabricators charge the finished edge by the foot: the front of the runs less the corners, plus any exposed ends and the island all round. A 4 in backsplash runs along the walls. Each sink and cooktop cutout is a separate charge.
Slabs and lengths
Granite comes in slabs of about 9 × 5 ft, quartz in jumbo slabs of 126 × 63 in (55 ft²). The calculator adds 15 % for layout and seams; the fabricator will lay out the pieces on the actual slabs. Laminate tops come post-formed in 6–12 ft lengths, one per run.
Common mistakes
- Counting corners twice. An L measured along both walls is a corner square too big.
- Forgetting the backsplash. Stone backsplash comes from the same slabs.
- Measuring before the cabinets are in. Final templates are taken on set cabinets.
For the floor in the same kitchen, use the Tile Calculator.