Why does my cat kick litter all over the floor?
Quick answer
Cats fling litter out of the box as part of their natural digging and burying behavior, but a box that is too small, litter that is too shallow, or sides that are too high can make the mess far worse.
The full answer
The most common causes are ordinary instinct plus a few fixable setup problems. Many cats scratch vigorously to cover their waste, and some kick up a storm right after going. A box that is too small leaves no room to dig, so litter ends up on the floor; aim for a box about one and a half times your cat's length from nose to base of tail. Litter that is only an inch deep gets scraped down to the bottom, sending grains flying, so keep it two to three inches deep. Very lightweight litters track and scatter more easily, and covered boxes or boxes with high sides encourage cats to perch on the rim and kick outward.
The practical fixes are straightforward. Switch to a larger box, add litter to the proper depth, and choose a high-sided or rimmed design; some cats also do well with a top-entry box. Place a honeycomb or two-layer tracking mat just outside the box to catch grains, and push the box against a wall to reduce scatter in one direction. Do not scold your cat for digging. It is an instinct it cannot suppress, and punishment only makes the cat anxious about using the box, which can lead to avoidance.