Even though I didn't pay close attention to the size (I thought they were a little bigger), I found these very useful. They are a decent thickness: thick enough to handle multiple uses and re-potting plants, but not so thick that you can't work with them. They will stack inside a standard seed starting tray-base perfectly. A good choice if you want to use all individual starting pots to make transplanting easier. The seedlings I planted in them grew well and established nice roots. The drain holes in the bottom are a good size.