Combined selection tool techniques are described in which selection of portions within an image is enabled via a tool configured to selectively switch between a coarse selection mode and a refinement selection mode. In one or more implementations, an image is exposed for editing in a user interface and input is obtained to select portions of the image using the tool. The selection mode is automatically toggled between the coarse selection mode and refinement selection mode based on characteristics of the input, such as position and velocity of the input or gestures mapped to the input. Then, selection boundaries defining the selection of portions of the image are modified in accordance with the input. In one approach, the coarse selection mode corresponds to a graph cut mechanism and the refinement selection mode corresponds to a level set mechanism.