A metaphor means that two things are the same in all ways. For example, He is a pig means that he is like a pig in many ways: size, appetite, manners, etc.
A simile, however, means that the two things are the same in 1 way. For example, He is fat like a pig or He is as fat as a pig means that he is very fat.
Comparison chart
 | Metaphor | Simile |
|---|---|---|
| Structure | A is B | A is like B OR A is as _____ as B |
| Similarity between 2 things | All attributes | 1 attribute |
Comments: Metaphor vs Simile