Algebra has been identified as a gatekeeper to careers in STEM, but little research exists on how algebra appears for practitioners in the workplace. Surveys and interviews were conducted with 77 STEM practitioners from a variety of fields, examining how they reported using algebraic functions in their work. Survey and interview reports suggest that linear functions may be ubiquitous in the workplace but that nonlinear functions are less often reported to be explicitly used. STEM practitioners report often using algebra functions as calculations or formulas rather than symbolic equations, and many justify the importance of algebra in its relation to statistics and data analysis. We provide recommendations for future research.