Diagonal Corner
Dealing with a diagonal corner (often called a "chamfered" or "clipped" corner, typically where a corner sink or a diagonal cooktop sits) can feel a bit like a high school geometry pop quiz.
However, fabricators calculate this using a trick that makes it much simpler: instead of trying to measure the weird triangular slices directly, you treat the entire corner as a **perfect square first**, and then you subtract the empty space.
## The "Square Drop" Method
Imagine your L-shaped counter meets at a sharp, 90-degree corner in the back, but the front has a flat diagonal face cutting across it. This creates a triangle of solid countertop in the corner, and a missing triangle of empty space where you stand.
**Measure the corner square**
*Treat it as a full box*
Measure from the very back corner of the wall out to where the straight edges of your countertops would normally end before the angle starts. This gives you a square area (e.g., 36 inches by 36 inches is standard for a diagonal corner cabinet).
Square Area: 36 \times 36 = 1,296\text{ sq. inches}.**Measure the 'clipped' edges**
*Find the missing triangle*
Look at the two sides where the countertop material was "cut away" to make room for you to stand at the angle. Measure the length of those two missing straight edges.
Let's say the missing triangle sides are 12 inches along the left counter edge and 12 inches along the right counter edge.**Calculate the triangle area**
*Base x Height / 2*
The formula for the area of a right triangle is:
Using our 12-inch example:
(12 \times 12) \div 2 = 144 \div 2 = 72\text{ sq. inches of empty space}.**Subtract the empty space**
*Square minus Triangle*
Subtract the empty triangle space from your total corner square area to get the exact material size.
1,296\text{ (Square)} - 72\text{ (Triangle)} = 1,224\text{ sq. inches}.**Convert to square feet**
*Divide by 144*
Divide your final square inch total by 144 to get the square footage of just that corner piece.
1,224 \div 144 = 8.5\text{ sq. ft.}
## The Reality of Fabricator Pricing
While the geometry above gives you the *exact physical area* of the finished stone, it is incredibly important to know how a fabrication shop will actually charge you for it:
> **The Slab Waste Rule:** Stone fabricators cut your angled corner piece out of a raw, rectangular slab of granite, quartz, or marble. Because the leftover triangular piece cut off the front is usually unusable waste, **most shops will charge you for the full square area** (36 \times 36\text{ inches}) without subtracting the triangle.
>
When estimating your budget, it is always safest to calculate the corner as a full, uncut square block. This ensures you aren't caught off guard by their material estimates.
