To change the font size while reading a document on a Kindle with keyboard, select the Text button on the keyboard, choose Right Arrow on the five-way controller key, and pick your desired text size. Push Text again to finalize font size changes, or tap the center of the controller.
Changing the font size on a Kindle depends on the type of device you use. Font size changes only apply to documents and not to menus or the Kindle Store. When changing the type size on a Kindle with keyboard, locate the Text key by finding the Aa button beside the space bar. After pressing the key, review the available text-formatting options on the screen. As of 2015, Kindle offers eight text-size options, which appear as a series of As at the top, with the existing text size being underlined.
To adjust the font size on a Kindle without keyboard, select Menu while opening a document, and push the right arrow on the five-way controller. The type size changes immediately when you press Menu again or push the center of the five-way controller.
Increasing the font size on a Kindle Touch or Kindle Fire, which are devices with a touch screen, involves placing two fingers on the screen and dragging the fingers apart. Take your fingers away from the screen to apply the changes.