The thickness of granite bathroom countertops can vary depending on personal preference and the type of granite being used. However, the most common thickness for granite bathroom countertops is 3/4 inch (2 centimeters). Some people may prefer a thicker slab, such as 1 1/4 inch (3 centimeters), for a more substantial and luxurious look. Ultimately, the decision on thickness should be based on aesthetics, budget, and the overall design of the bathroom.