Granite countertops are formed from massive blocks of natural stone quarried from the earth. The blocks of stone are sliced or cut into smaller portions that can be transformed into counters, tiles or other building products. When the slabs are cut, they may be sliced into sections of varying thickness. Some of these thicknesses are frequently used as countertops; others may also be used as countertops on a special request basis. In all, there are three common standards for counters as well as some other variations.
2 cm or 3/4 inch
The thinnest granite slabs available are 2 cm or 3/4 inch thick. This size is typically reserved for bathrooms, because the thinner stone is usually found in smaller pieces. However, many homeowners use the thinner stone in their kitchens as well.
Slabs of granite 2 cm thick are less expensive and lighter than thicker stones. They may be used around the perimeter of the kitchen, or on peninsulas, work areas or desk areas in the kitchen. It's not uncommon to purchase the thinner stone and build up its edge to make it appear thicker than it is, to save money.
3 cm or 1 1/4 inch
The most commonly found granite countertop thickness is 3 cm or 1 1/4 inches. Nearly all stones are found in this size, and the slabs can be as large as 105 by 54 inches. This allows the homeowner to choose a slab that permits long runs of cabinetry and features fewer seams, or creates a single slab that covers the entire kitchen. A 1 1/4-inch granite countertop provides a thicker edge profile, which is beneficial for decorative edges such as ogee or dupont. The thicker granite can also extend farther from the cabinets without requiring support, which helps homeowners who want to extend the edge to provide seating at the counter.
Less common than the other sizes of granite, but still considered a standard thickness, is the 2-inch thick granite slab. Two-inch thick slabs are typically much more expensive than the other common stones, but they do have some positives.
The thicker granite can be carved into specialty edges which may include multiple steps or layers. The thicker granite can also extend out even farther from the cabinets without support, giving additional depth to counter seating along with a clean and modern look.
Because of the expense of the 2-inch thick slab, it's generally only used on specific areas of the kitchen, including islands, peninsulas or buffets.
While there are three standards of granite slab counters, other sizes are available. For example, granite tiles are 3/8 inch thick and are installed over a plywood underlayment. Because a granite tile must cover the face or front of the counter as well, many granite tile counters will be approximately 1 inch thick in total.
The other standard in granite counters is the built edge, which consists of a 4-inch wide piece of granite in the same thickness as the counter itself. This is attached with epoxy to the underside of the granite's edge and ground down to a finish that matches the rest of the counter. This provides a thick, decorative look to the counter for less money than a thicker slab, and in some cases may produce a slab that appears to be up to 3 inches thick.