Efforts to increase the number of young people in England studying mathematics post‐16 have historically focused on participation in standalone mathematics qualifications. However, following the recent A‐level reforms, many advanced level students are engaging with some form of mathematics through the mathematical content now formally embedded within other subjects. To offer a more comprehensive view of the mathematics being learned post‐16 we present a framework analysis of the subject content documents of the 19 A‐level subjects with a required quantitative component, using a recently developed framework of General Mathematical Competences (GMCs). Results are visualised as maps showing the presence of GMC sub‐competences for individual A‐level subjects and combinations of subjects. The application of the GMC framework in this new context provides a much‐needed common language for cross‐curricular discussion of the types of mathematics present in different subjects, with implications for interdisciplinary mathematics learning and curriculum alignment between post‐16 and higher education across the disciplines. In addition, the framework highlights the non‐binary nature of mathematics participation, calling into question what counts as participating in mathematics in the post‐16 phase.