Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for implementing a dynamic space bar are disclosed. In one aspect, a method includes the actions of determining, by a computing device that includes a touchscreen keyboard and trackpad, a context of the computing device. The actions further include receiving touch input on the trackpad. The actions further include designating, by the computing device and based on the previously-determined context of the computing device, the touch input on the trackpad to be a selection of a space bar of the touchscreen keyboard. The actions further include providing, for output to a display of the computing device and based on the computing device having designated the touch input on the trackpad to be a selection of the space bar, an indication of the selection of the space bar.