Sediment bulk density is the total mass of mineral and organic sediment within a defined volume. It is a key variable in many research questions pertaining to Bay sediment studies but one that is often poorly quantified and can be misinterpreted. The motivation for this report comes from a recommendation by Schoellhamer et al. (2018) to compile more accurate estimates of bulk density of Bay sediments to convert between volume and mass with a higher level of certainty. Through funding and guidance from the Bay Regional Monitoring Program Sediment Work Group, this report is a first step towards compiling the available data on sediment bulk densities across Bay habitats and along salinity gradients to provide better information for resource managers and others working on sediment-related issues. This report discusses the need to know the bulk density of Bay soils to convert between sediment mass and soil volume; clarifies general definitions and common points of confusion related to sediment bulk density; compiles primary sources of bulk density measurements, secondary sources of bulk density estimates, and standard engineering estimates of bulk density for different habitats in San Francisco Bay; and, provides a database where practitioners can track, analyze, and share bulk density measurements.