The fuel gauge in the car starts to light up: How many kilometers can I still manage “in reserve”?. As a rule of thumb, there is usually around 50 kilometers left when the display lights up.
But you shouldn't push this to the limit. According to experts, anyone who runs their tank empty, including every last drop, risks expensive damage to the fuel system. In a test by ADAC, no display promised more range than was actually possible. The vehicles even went further than promised: between 8 and 60 kilometers more than predicted by the on-board computer.