They're about scooter sized I'd say.
MINE is big enough for an adult to ride. 72 inches long and at the seat 3 ft or so tall. I bought it as a starter just to get the feel of shifting and riding. It is upgradeable to 300cc's. I actually have another one for sale on EBAY. These are not toy type bikes, they were built to upgrade with ease, and they can carry Pagsta Roadsta or some people call them mini harlee's. Johnny Pag made both. Some of the mini Harlee's are only 51 inches long.