University of Tabriz Jurisprudence and Islamic Law 28210891 12 24 2021 09 23 Comparative Study of Loss of Use in the United-States and Iranian Legal Systems Comparative Study of Loss of Use in the United-States and Iranian Legal Systems 1 31 13954 10.22034/law.2021.13954 FA Mansour Amini Associate Professor, Shahid Beheshti University Mona Abdi PhD Student in Private Law, Shahid Beheshti University, Tehran Journal Article 2021 01 21 One of the most important requirements for claiming damages is certainty of damages. In order to be able to claim a damage, it is not enough to speculate it, but it is necessary to determine damages with certainty. Loss of use is such damages the occurrence of which is certain but the amount of damage is uncertain. This kind of damage often occurs in civil responsibility and the case of accidents. In our legal system, despite its importance and extensive use, this kind of damage has not yet been analyzed by the legal authors. In this article seeks to introduce this damage with pros and cons of acceptability of it and also the most important differences between loss of use and loss of profit and the common methods of assessing and calculating of this damage. Findings of this research show that the acceptance of this damage is necessary to achieve the fundamental “principle of full compensation” in all legal systems and it does not seem to be a barrier for accepting it in our legal system, particularly based on the articles 328 & 331 of civil code. One of the most important requirements for claiming damages is certainty of damages. In order to be able to claim a damage, it is not enough to speculate it, but it is necessary to determine damages with certainty. Loss of use is such damages the occurrence of which is certain but the amount of damage is uncertain. This kind of damage often occurs in civil responsibility and the case of accidents. In our legal system, despite its importance and extensive use, this kind of damage has not yet been analyzed by the legal authors. In this article seeks to introduce this damage with pros and cons of acceptability of it and also the most important differences between loss of use and loss of profit and the common methods of assessing and calculating of this damage. Findings of this research show that the acceptance of this damage is necessary to achieve the fundamental “principle of full compensation” in all legal systems and it does not seem to be a barrier for accepting it in our legal system, particularly based on the articles 328 & 331 of civil code. https://law.tabrizu.ac.ir/article_13954_008ebc37e48e56c8ca50f92eecd3c083.pdf