Solar simulators are the instruments that are used to measure the electrical characteristics of photovoltaic (PV) cells and modules. The PV characteristics are measured at standard test conditions (STC), which are achieved by maintaining an irradiance level of 1000 W m−2, 25 °C temperature, and AM1.5G irradiance spectrum. However, in case of a variation in any of these parameters there will be a deviation in the measured electrical characteristics of the test specimen from standard values. The uncertainties in calibration and measurement system of the simulator can also have significant impacts on power measurements. In this study, an estimation of the uncertainty in the measurements of current, voltage, and power is done by using a polycrystalline silicon PV module and a class A pulsed-type solar simulator. The results are compared with those obtained from other studies of similar nature to assess the accuracy of measurements. The findings show that if the maximum possible uncertainties are considered for a typical class A simulator, the power measurements can have a variation up to ±3.7 % from the true value for a 68 % confidence level and up to ±9.6 % for a 99 % confidence level.