The purpose of the study is to determine how web design and interface can affect the purchasing decision of consumer at group buying websites. With the growing e-commerce industry, businesses assume that websites are a big key to their success when there is an increased number of visits and purchases. Based on statistics and industry analysis, there is a growing population of consumers transferring to digital purchases in the Philippines, but they need to keep up with the demands of the customers and prevent unsuccessful purchases that leads to a loss of profit for the website. To proceed with the study, the researcher had (1) to assess the current performance of existing business to business to consumer e-commerce websites; (2) to identify the significant factors that affect the decision of design and interface development of B2C e-commerce websites; (3) to integrate those factors into developing a suitable webpage design and interface for business to business to consumer B2C e-commerce websites. ANOVA and regression were used as the statistical treatment of data. The study was able to confirm through the comparison of usability tests that the proposed website has significant improvements that can be used to improve the webpage in terms of web design and interface. The study will benefit online shoppers, entrepreneurs and the future users of the website.