A generic computer model is developed to calculate the laser fluence required to produce a specified depth of ablation in a material, as part of an integrated experimental and theoretical programme on laser ablation. Although the model has been designed around ultraviolet excimer laser light 308 nm and metal targets, its generalisation to other wavelengths will be discussed. The effects of melting, and absorption of laser light, in the emitted plasma plume, are included in the model.