This formula sheet covers the major quantitative relationships in chemistry from high school level through third year undergraduate, organised by topic. Each entry shows the formula, a variable key, and where relevant a link to the corresponding interactive calculator on this site. The level badges indicate the typical year of first encounter: HS for high school, Y1 for first year university, Y2 for second year, and Y3 for third year. Use the search bar to find any formula by name, variable, or keyword, or the filters to view only specific sections. All constants used throughout are as listed in the final section above.