How far can you drive after the low fuel light comes on in a 2006 Mazda 6?

It is a good practice to fill up when the tank is 1/4 full and never let it get below 1/4 full. You can easily suck trash from the bottom of the tank and clog the fuel filter. A partially clogged fuel filter, overworking the pump, is a major cause of fuel pump failure. But to answer your question, I don't recommend it, but, you can easily drive 25 miles after the light comes on. Beyond that is pure speculation. It all depends on how much the reserve is on this car. Normally it will be 2 gallons.