The present work proposes an accurate method for estimating the five physical parameters of photovoltaic (PV) modules from their experimental current–voltage characteristics and datasheet information using a single-diode equivalent circuit model. This method is based on the calculation of the series resistance $$R_{\mathrm{s}}$$ and ideality factor n using analytical formulations and manufacturer datasheets for the PV module, with the other three parameters (shunt resistance $$R_{\mathrm{p}}$$ , saturation current $$I_{\mathrm{s}}$$ and photocurrent $$I_{\mathrm{ph}})$$ estimated by solving a linear system of three equations using the least squares method. The proposed method is applied to experimental characteristics extracted from datasheets for the KC200GT and SQ80 PV modules. The extracted parameters show good agreement with those obtained by other methods, and the simulated I–V characteristic exhibits the best fit with experimental data. This method is accurate even in the presence of noise errors in measurement.