Digital payment systems are growing fast and changing how people, especially students, handle money. This study looks at why college students use the Unified Payments Interface (UPI). It combines ideas from two models: the Technology Acceptance Model and the Unified Theory of Acceptance and Use of Technology. The study checks how things like usefulness, ease of use, trust, social influence, and financial knowledge affect students' intentions and actual use of UPI. Researchers used a survey to collect data from 650 students online. They analyzed the data using statistical methods like chi-square, t-tests, ANOVA, correlation, and regression. The study found that usefulness is the biggest reason students intend to use UPI, followed by ease of use, trust, social influence, and financial knowledge. Intentions strongly affect actual use, supporting the models' ideas. Gender doesn't affect UPI use, but education level does. Students like UPI because it's convenient, fast, efficient, and easy to use. Other studies also say trust, convenience, and financial knowledge are key for using financial technology. This study helps understand why students use UPI and gives advice to fintech companies, policymakers, and schools to improve digital payment use.