Proportional monetary fines, as one of the novel and purpose-oriented forms of financial punishment, are designed based on the principle of proportionality between the crime and the penalty, taking into account the offender’s financial and social circumstances. They are considered among the significant measures aimed at promoting justice in response to financial crimes within the Iranian criminal justice system. In this system, the amount of the fine is not determined by a fixed figure; rather, it is calculated based on the benefit derived from committing the crime, the extent of the damage caused, and the financial capacity of the offender. the purpose of this mechanism is to prevent the ineffectiveness of punishment against offenders with substantial financial resources, for whom fixed monetary penalties are practically non-deterrent. Despite its numerous theoretical advantages, the implementation of this criminal law institution faces several obstacles in practice. These include the lack of clear legal guidelines for determining the minimum and maximum fines, the absence of a consistent judicial practice in dealing with recidivism, the conflict of this mechanism with the principle of personal liability of punishments, the risk of inequality in the administration of criminal justice if the offender’s assets are not accurately assessed, and the conversion of monetary fines into imprisonment in cases of non-payment, which can undermine the very spirit of the institution.

From a theoretical standpoint, proportional monetary fines result from the convergence of two major approaches in criminal philosophy: retributivism and utilitarianism. Retributivism, emphasizing the proportionality between the crime and the punishment, justifies the legitimacy of this type of penalty based on its correspondence to the benefit gained from the offense. In contrast, utilitarianism, relying on the principle of deterrence, views this mechanism as an effective tool for reducing the incentive to commit financial crimes. especially in today’s economic context, the link between criminal justice and economic efficiency has highlighted the necessity of the purposeful use of such instruments. This study, using a descriptive-analytical method, examines the theoretical foundations, strengths, weaknesses, and practical challenges of proportional monetary fines, emphasizing the need for legislative reforms, clarification of the enforcement structure, and the development of coherent judicial guidelines. Such measures are essential to enable this mechanism to function as an effective, fair, and economically proportional tool within society.