To answer your question in a way that makes sense, I'd need more information. Here are some possibilities:
* Are you asking about the size of a specific monkey? Different monkey species come in many sizes, from the tiny pygmy marmoset (5 inches tall) to the massive mandrill (3 feet tall).
* Are you asking about the size of a baby monkey? Baby monkeys are obviously much smaller than adult monkeys.
* Are you making a joke? If so, I'd love to hear the punchline!
Please tell me more about what you're asking so I can give you a better answer! 😄