Breach of contract occurs when a party fails to perform a term of a contract to which they are a party without lawful excuse. This usually gives rise to the ability of the other party or parties to the contract to seek remedies in damages, specific performance or injunction. In rare cases, it may give rise to the remedy of recission,
However, not all breaches of contract are treated equally. Damages are almost always an available remedy, but specific performance and injunction are rarely awarded and recission is almost never awarded unless the breach amounts to complete non-performance of the contract.
Remedies in breach of contract are available when there is a breach of both an express term of a contract, or an implied term of a contract.
Many contracts create special remedies available to the parties if one side is in breach. For example, a common remedy available in a contract for payment of a debt for a chattel over time is the right to take posession.
However, a party who suffers a breach is often not able to "sit on their rights", even where the language of the contract is unambigious and cannot be changed without the consent of both parties. See estoppel and gratuitous promise.