Much bigger than I expected. My other litter box with the side extenders is still a little shorter then this box. This box also holds a lot more litter than my other litter box as well. I was really hoping the bigger sides would help stop the cats from throwing out so much litter but I think thats a lost cause. I can literally hear my cats spend 1-2 minutes scratching in the litter to cover something up which of course some goes over the edge and onto the floor. Im starting to think the only litter box that will stop that is a huge tote box. This box works well, not really any flaws that I can see.