The cost of UI UX development services depends on several factors, and the client's needs are the most crucial. Let's look at 3 common situations when clients' needs may affect the final app design cost. No App: need to build an MVP/Prototype to test the market. Time & Money: 1-1.5 months, ~ $8K. Existing app: need to improve the app's features. Time & Money: 2.5 - 3 months, $15 - 20K. Existing app: need to rebuild the app from scratch. Time & Money: 3 - 4.5 months, ~ $20K. The cost of UI design and UX design depends on several factors, and the client's needs are the most crucial. Let's look at 3 common situations when clients' needs may affect the final app design cost.