The OntheGo™ Bluetooth Mouse does not show an exact battery percentage on your computer. Instead, the LED in the center of the DPI button, just below the scroll wheel, shows the status. It glows red while charging and turns green when fully charged. When the battery runs low, the LED flashes as you use the mouse, and if it drains further the mouse powers off on its own to protect the battery. Note that pressing the DPI button also makes the LED blink to show the current DPI setting, which is separate from the battery indicator.