A forehead thermometer measures the body temperature on the basis of infrared. This way is simple because it is quick and simple. The measurement also takes place contactlessly, which increases hygiene. By keeping the forehead thermometer at a specified distance from the forehead, the heat radiation measures the temperature. This measurement is easy for children because it is also an option during sleeping. Because the heat of the forehead is mainly measured, it gives an indication of fever, but you do not get a reliable core temperature.