This a small but mighty oven. The summers have gotten so hot near Denver, Colorado that I don’t even turn our indoor oven on. We put this oven in a protected spot outside and I can cook to my heart’s content! (Of course we always bring it in when finished) It preheats in 4 minutes. I have made birthday cakes, muffins, cookies, casseroles, etc. It will hold a 9X13 pan (as long as it doesn’t have handles), a standard 12 cup muffin pan, a bundt pan, a square 3+ quart casserole dish (the lid won’t fit, I cover it with foil) and a 9 inch square pan. Since it won’t hold a cookie sheet, I use a 9X13 brownie pan and the bottom half of the broiler pan. I like using the convection for the smaller baked goods. I love this oven so much that my friend bought one after hearing me rave about it! It’s also just the right size to fit in one of my lower cupboards when not in use. I highly recommend this oven!