In an educational context, the accurate determination of each student's socioeconomic status (SES) is important for planning, reporting and general institutional research. This article describes a project undertaken to develop the means to derive a proxy measure of students' SES, based on home address location and Australian Bureau of Statistics (ABS) data, using free Geographic Information System (GIS) software. [This article was first presented at the Annual Conference of the Australasian Association for Institutional Research, "Evolution of IR practice and use of IR," Terrigal, New South Wales, November 12-14, 2013.]