Biomass is widely reported as a non-homogeneous fuel, with properties varying depending on its origin or the geographical region where it is obtained. Because of that, the development of predictive equations which are specific for the characteristics of certain regions' biomass is recommended. In this work, some correlations were obtained to relate the higher heating value (HHV) of a hundred Spanish-based biomass samples to their proximate analysis data. Some hybrid equations, using both proximate and ultimate analysis data are also proposed. Carbon, oxygen, ash and fixed carbon contents proved to be the most important values, while including moisture greatly improves them. As a result four equations were obtained with errors close to 5% for the tested samples, which representing a contribution to low cost routines to estimate and normalize the characterization of single or composed solid biofuels. (C) 2013 Elsevier Ltd. All rights reserved.