They can be synonyms when used to express the idea of something being in addition to (as they are in Caner's examples), but 'too' has other meanings. The examples below are from http://dictionary.reference.com/browse/too - you can only substitute 'as well' for 'too' in examples 1 and 4. 1. in addition; also; furthermore; moreover: young, clever, and rich too. 2. to an excessive extent or degree; beyond what is desirable, fitting, or right: too sick to travel. 3. more, as specified, than should be: too near the fire. 4. (used as an affirmative to contradict a negative statement): I am too! 5. extremely; very: She wasn't too pleased with his behaviour.

As well and too have the same meaning, let me give you an example, i went to the hospital too or i went to the hospital as well.

Just a few examples: He's got a degree in Physics and he speaks three languages too. He's got a degree in Physics and he speaks three languages as well. I go out a lot, but I like staying in and reading as well. I study very hard but I like playing golf too. I hope that helps.