As reporting of effect sizes in evaluation studies has proliferated, researchers and consumers of research need tools for interpreting or benchmarking the magnitude of those effect sizes that are relevant to the intervention, target population, and outcome measure being considered. Similarly, researchers planning education studies with social and behavioral outcomes need sources of appropriate effect size values for conducting power analysis. In this paper, we use a large meta-analysis to provide estimates of distributions of effect sizes that may be helpful for researchers and consumers of research to assist in interpreting the magnitude of effect sizes. These distributions can also be used to select effect sizes for power analysis for school-based randomized trials of interventions with social and behavioral outcomes. We introduce the Effect Size (ES) Contextualizer application (https://ebcontextualizer.shinyapps.io/EmpBench/), which summarizes the effect sizes in the meta-analysis and allows researchers to use the database to do their own benchmarking or study planning. [This paper was published in "Journal of Research on Educational Effectiveness" 2024.]