The detonation propensity of hydrogen-air mixtures with addition of methane, ethane or propane in wide range of compositions is analyzed. The analysis concerned the detonation cell width, ignition delay time, RSB and parameters. Results are presented as a function of hydrogen molar fraction. Computations were performed with the use of three Cantera 2.1.1. scripts in the Matlab R2010b environment. The validated mechanisms of chemical reactions based on data available in the literature were used. Six mechanisms were assessed: GRI-Mech 3.0, LLNL, SanDiego, Wang, POLIMI and AramcoMech. In conclusion, the relation between detonation propensity parameters is discussed.