This work presents a new formula to calculate the surface tension of silicon based molecules. As a first step, the raw surface tension data of silanes (experimental, smoothed and predicted) accepted by DIPPR database were collected. After the data analysis, only the experimental and smoothed data were considered for the calculations. The selected data were regressed with a scaled equation based on four input parameters: radius of gyration, critical density, critical temperature and acentric factor as fluid constants. Particularly relevant is the introduction of the radius of gyration as fluid parameter, that is a noticeable difference with respect to other previous literature methods. The selected data also were analyzed with the most reliable semi-empirical correlating methods in literature based on the corresponding states theory. The proposed equation is very simple and gives noticeable improvement with respect to existing equations (AAD = 3.7%). (C) 2015 Elsevier B.V. All rights reserved.