Abstract: The invention relates to a process for calibrating a calorimetric flow indicator to a medium to be measured. The flow indicator has a sensor element that provides a temperature-dependent resistance and which heat up in a short period of time by means of electrical current heat. The resistance variation of the sensor element represents a measure of the flow velocity of a medium flowing by the sensor element. The calorimetric flow indicator is set for a specified medium other than the medium to be measured, with a resistance value Ro at a zero flow and a resistance value R.sub.max at a maximum flow, defining a preset range of measurement R.sub.max --Ro for the specified medium.