Most times, people tend to use both Tomato paste and tomato sauce interchangeably. As similar, as they might sound, there are some little differences between them. The first difference between tomato sauce and paste can be explained through the various ways the two can be prepared. Tomato paste is prepared by cooking tomato that has been ground and crushed together with a little quantity of water for a particular period of time until it is thick enough.
Tomato sauce, on the other hand, is prepared when tomatoes have been ground and crushed into a thick liquid together with the addition of other ingredients like garlic, basil, etc. Another is that through your tomato paste, you can make your tomato sauce. This can be done by simple dilution of the tomato paste. In terms of thickness, tomato paste is prepared very thick, which tomato sauce is not as thick as tomato paste.