Global calculations of the radiative forcing due to contrails from aircraft are performed. A contrail distribution computed based on aviation fuel consumption and radiative transfer models for solar and thermal infrared radiation have been used. A substantially smaller net radiative forcing due to contrails (about 0.01 Wm-2) is estimated in comparison to former studies, emphasizing the strong sensitivity of this value to uncertainties in the longwave and shortwave contribution. The solar forcing is negative and the magnitude maximizes for high solar zenith angles. Altering the time for aircraft traffic has the potential for reducing the radiative forcing due to contrails, and under certain assumptions made in this paper giving a net zero forcing. ¿ 2001 American Geophysical Union