The Seebeck coefficient of thermopile infrared (IR) sensors is a crucial parameter. The ability to rapidly and in-situ extract the Seebeck coefficient across a wide temperature range is advantageous for assessing the impact of temperature on sensor's performance. In this study, specific sets of current excitations are used, the exothermic and endothermic temperature changes caused by Peltier effect are offset, and the Seebeck coefficient of sensor over a wide temperature range (300–600 K) is extracted from Joule heat by measuring the resistance of sensor. The effectiveness of this method is evaluated by a thermopile IR sensor. The maximum relative error between the results obtained from this method and specialized instrument does not exceed 9 %.