This chapter focuses on quantifying the costs of environmental noise in monetary terms (monetisation) that can be used for taxation of travel and freight activities producing unwanted noise and other externalities. Monetisation also allows acoustic consequences to be included in economic analyses of infrastructure investments, efforts to reduce noise and efforts to improve the acoustic environment. It is when the external costs of noise are used for taxation and the economic benefits of an improved acoustic environment are included in the planning of transport and building infrastructure, urban and regional development processes that they affect policies and decision-making. Finally, we mention some of the shortcomings of current approaches and the scope for further research and caveats.