Laser ablation of silicon is investigated with a large set of laser parameters to determine the ablation rate over five laser fluence decades. A thermodynamic model approach for the ablation of silicon has been derived. This simplified model determines the achievable ablation depth per pulse as a function of the applied laser fluence ranging from femtosecond to microsecond laser pulse duration. Furthermore different laser wavelengths from near-infrared to ultra-violet are investigated to determine the dependence on the optical penetration depth and on the ablation efficiency. The measured ablation depth per pulse is in agreement to the models predictions with the restrictions made.