Abstract Aims Potent P2Y12 inhibitors for dual antiplatelet therapy (DAPT) is crucial for managing acute myocardial infarction; however, the selection of drugs is based on limited clinical information such as age and body weight. The current study sought to develop and validate a new risk scoring system that can be used to guide the selection of potent P2Y12 inhibitors by balancing ischaemic benefit and bleeding risk. Methods and results Derivation cohort of 10 687 patients who participated in the Korea Acute Myocardial Infarction Registry-National Institutes of Health study was used to construct a new scoring system. We combined the ischaemic and bleeding models to establish a simple clinical prediction score. Among the low score group (n = 1764), the observed bleeding risk (8.7% vs. 4.4%, P < 0.001) due to potent P2Y12 inhibitors exceeded ischaemic benefit (1.3% vs. 2.2%, P = 0.185) during 12 months. Conversely, the high score group (n = 1898) showed an overall benefit from taking potent P2Y12 inhibitors from the standpoint of observed ischaemic (17.1% vs. 8.6%, P < 0.001) and bleeding events (10.1% vs. 6.8%, P = 0.073). The performance of ischaemic [integrated area under the curve (iAUC) = 0.809] and bleeding model (iAUC = 0.655) was deemed to be acceptable. Conclusion The new scoring system is a useful clinical tool for guiding DAPT by balancing ischaemic benefit and bleeding risk, especially among Asian populations. Further validation studies with other cohorts will be required to verify that the new system meets the needs of real clinical practice.