Agreement: An agreement is a proposal / promise / set of promises that is given by a party to another party without any legality thus this proposal doesn't bind by the law denotes Agreement. An agreement can be done anywhere without thinking because this doesn’t enforceable by the law of respected state. 

Contract: An agreement that done between two legal parties and both are aware of their agreement and this agreement are binded by the law defines Contract.  Contract need to be written in a document because it act as prove.

Difference:

• Contract are formal promise that are bound by the law, Agreement are informal promise that doesn’t involve any enforcement of law.
• Anyone can make an agreement/ Only Major parties (18+) can make contract.
• Agreement can be on any object / Only legal objects are needed for contract. 

This is a short conceptual framework of contract and agreement which was taught in our class.