Abstract-With the popularity of the websites, online business can generate more benefit and possibly be success rapidly. One key success factor is the usability of the websites. Three quality characteristic factors based on usability are investigated, i.e., user experience, functionality and user interface usability. User experience concerns with aesthetic attributes, functionality checks for the appropriate functions, and user interface usability focuses on a good UI design or easy-to-use website. Furthermore, an approach to measure usability including measuring metrics is proposed to assess the tasks related to online hotel reservation. Searching hotel, displaying search result, displaying room detail, and making a reservation tasks are evaluated their usability scores with fiverating Likert scale by the sample group of users. The empirical result shows that the rating score conforms to the rank and reflects the performance in use of the website. Booking.com has highest rating score of 4.11 while Hotels.com and Agoda.com have equal rating score of 4.09. Combining the best parts of each website can produce the website with higher rating score of 4.20.Index Terms-Usability, hotel reservation, user experience (UX), functionality, user interface (UI).