What does sandpaper grit size mean?

The grit size of sandpaper refers to the size of the abrasive particles on the paper. The lower the number of the grit size, the coarser the sandpaper. Coarse sandpaper (e.g., grit 40) is used for quickly removing material, while fine sandpaper (e.g., grit 400) is perfect for smoothing surfaces and applying a finishing layer. Choose the right grit size depending on the task you want to accomplish!