Is your furnace thermostat bad well the furnace dont stay on long it stays on for 45 seconds to a minute then kicks off for about five minutes is my thermostat bad?

Furnaces that cycle on and off frequently like yours does can have a few possible reasons that may or may not be part of the thermostat. A digital thermostat may not be the reason, but an old thermostat with a Mercury switch inside which moves when the bimetal strip heats and cools down is a possibility. If the thermostat has an electrical problem (only 24 volts) could be causing the bimetal strip heat up fast, simulating the room getting warm. Another possibility is inside the furnace heat exchanger area. There is a safety device which turns off the furnace and fan when it gets hotter than it is supposed to, so you don't burn down your building. (this supposes that you have a forced air furnace which you did not mention or not) If you have a wall heater, it has a similar type of high temperature cut out. These temperature cut out devices are not very expensive and can be replaced fairly easily. Have someone just check the wiring of the thermostat by unscrewing it from the wall to see if there are any problems with the wires as well as verifying that it is or is not a mercury bulb controlled device.