This is a ‘quantitative methods’ chapter. It describes the basic quantitative concepts in corpus linguistics. These are: frequency and normalised frequency; range and dispersion; the concept of keyness; collocation; and lexical bundles. In each case research using these ideas is discussed and issues around the different available measures are presented. The chapter then introduces multidimensional analysis and how quantitative studies might be enhanced by semantic and other annotation. The emphasis in the chapter is on how the various measures are used and the impact they have on the applications of corpus research.