In jurisprudential and legal terminology, uncertainty is said to be one of the variables that is at risk due to ambiguity in the financial and economic balance in exchange contracts. It is not known whether the consideration paid for it has an economic balance with it or not. Therefore, it is possible to think that uncertainty has refrained from the ambiguities of dealings, which are in matters outside of Awadin, such as the term and period that are seen in the contracts. But this assumption can be undermined; Because ignorance, where it directly or indirectly affects the economic value of the exchange, can spread to the transaction itself and make it unknown. In this regard, the terms of the contract that affect the value of the exchange directly or indirectly, as soon as they are considered clear from the perspective of custom, are sufficient to avoid disputes and should not be strict outside of this circle. On the other hand, ambiguity in contractual deadlines, if the risk caused by ignorance is considered to be effective from the point of view of custom, it is considered effective in creating confusion. Finally, it should be acknowledged that today's different interpretations of custom have sometimes caused confusion in the field of opinion and in the field of judicial procedure in identifying the examples of definite and firm contractual terms and, consequently, void of confusion. In this research, by collecting information from library and digital sources and using analytical method, we have tried to discover the ruling and analyze it and provide solutions