Communication plays a vital role in design — in order to be successful your products have to clearly communicate their intent and purpose. When we talk about communication, we usually mean text, because the purpose of text in your app is to establish a clear connection between the app and user, and to help your users accomplish their goals. Typography plays a vital role in this process; good typography makes the act of reading effortless, while poor typography turns users off.
How do you make typography work for you and your users, and not against you and them? Unfortunately, there are a lot of conflicting opinions out there about best practices for typography on mobile, and there isn’t one strict set of rules that apply in every case. However, there are several things you can do to make sure the typography is honoring the content and improve readability on mobile devices.
Font Size, Line Length, and Space
Three of the most important considerations when designing type for mobile devices are font size, line length, and space. Type must be large enough to easily read, and there should be sufficient space between lines.
The size of your text has a huge impact on the experience of reading something on screen. It takes the user much longer to process smaller text. Text that is too small can cause the reader to strain, because it’s usually hard to find the beginning and end of lines of text when there are too many letters to digest at one time. As result, users will skip most of the information presented. This is especially true for mobile, where tiny type on a small, bright screen can be a real headache for users.