Some people may not immediately understand the difference between the two. One of the main differences is when you say capitalism, this banks on the importance of protecting private enterprise and the proprietorship so that the development of a free market is possible.
This can also be used to increase the capital of various companies. When you say libertarianism, this means that each individual who is living in this world right now will come with his/her individual rights. It is obvious that capitalism is meant to promote and protect the various corporations more than the individuals while libertarianism is the opposite because it is meant to protect different individuals.