This chapter examines how human activities and infrastructure can be expressed in terms of various types of footprint. It explores how these can be used as benchmarks for comparing different lifestyle choices, design or strategies using techniques such as carbon footprinting, ecological footprinting, water footprinting and biodiversity indicators. The concept of ‘One Planet Living’ is explained and tools are introduced that can be used to determine how many planet equivalents humans require to maintain living standards and growth, whilst tracking the number of earths required to support humanity in terms of ‘global overshoot in planet equivalents’. The reader is guided through the numerous tools that have been developed for calculating footprints for everything from the individual to whole countries.