It's a little bit difficult to give a concrete answer to your question, because anatomy can vary from person to person, and not all of the muscle tissues of the human body can be neatly differentiated from one another. Even physicians and muscle specialists disagree as to the precise count of muscles in the body. That being said, here are some estimates:
The scientific community is generally in agreement that there are about six-hundred and forty skeletal muscles in the human body. These are the muscles which connect to and lie alongside bone and help us perform activities like walking, lifting, and balancing. There is also cardiac muscle-- the heart-- and smooth muscle, like the muscles of our digestive tract. Combining these three types of muscle, an estimated total of muscles in the human body could be as high as nine-hundred.
Unfortunately, this estimate doesn't account for lots of the teeny-tiny muscles that are so difficult to count but play an important part in our well-being. There are numerous vascular sphincters in the circulatory system which help to regulate the flow of blood throughout the body. These sphincters are made up of muscle! Are you familiar with the sensation of your arm hairs standing on end when you get cold? Perhaps you have heard it called "goose-bumps?" There are millions of tiny muscles working to help your body hairs stand up or lie flat. Because muscles like these are so small and so numerous, it is difficult for us to know exactly how many muscles there are in the human body at this time.