The performance of a contract is the ultimate goal of each contracting party, and the sanctions for its violation varies depending on the legal system, from requiring the performance of the contract itself to terminating it. However, the injured party may grant the other party a new period of time to perform the contract. By granting a period of time, two immediate effects occur: Firstly, it is not possible to invoke performance guarantees that conflict with the granting of a grace period during that grace period. Secondly, the granting of a grace period does not affect the acquired rights of the grantor of the grace period, namely the right to terminate and claim damages resulting from the delay in the performance of the contract. The recognition of this doctrine, which has its roots in German law, is in harmony with several principles of contract law that today adorn many national and international legal documents, such as the preservation of the contract, interpretation in favor of the contract, good faith, prohibition of contradictory conduct, reasonableness, etc. This article intends to evaluate, in a descriptive and analytical manner and in a comparative manner, the doctrine of granting additional time in the Vienna Convention, the Principles of European Contract Law, the Principles of UNIDROIT, and Iranian law. In short, it can be said that identifying this doctrine is a step towards preserving the contract and the security of legal relations, and therefore it is reasonable in harmony with the principles governing the contract.