A growing number of K12 and college educators are using the collection of interactive simulations developed by the PhET Interactive Simulations project at University of Colorado Boulder. The design of each simulation seeks to support educators in achieving a range of pedagogical goals through implicit scaffolding. To decrease barriers to adoption, the simulations are designed for flexible use, available free of charge, and usable across platforms. The resulting simulations are compatible with diverse learning goals, implementation contexts, pedagogical approaches, grade levels, and learners. While website statistics establish that over 45 million simulations are run per year, these statistics provide little information about who uses the simulations and how they are being used. Here we report on analysis of responses to a large-scale, self-report survey from 1,233 high school and 276 college educators who are using PhET in their physics instruction, to provide insight into who uses PhET simulations, with which populations of students, towards what pedagogical goals, and with what instructional approaches. We found that new and experienced teachers use simulations, with diverse student populations, and to support a wide range of pedagogical goals. The responding high school and college educators were found to be similar in the goals they intended use of PhET simulations to support (for example, to develop conceptual goals, and to conduct science inquiry), but differed in their instructional approaches.