Quantifying the flow of matter and energy through food webs provides insights into population and community dynamics and ecosystem functioning. Knowing the energetic value of specific food sources and their availability to consumers is vital to understanding the transfer of energy through food webs. So far, the relationships between different biomass measures and energy content have not been established for many temperate Australian benthic organisms. Through extensive multi-seasonal sampling of key benthic macrofauna in the Coorong, a hypersaline estuary and lagoon at the mouth of the Murray River in South Australia, we established relationships between biomass measures of wet mass and dry mass with energy content determined from bomb calorimetry. Correlations between wet and dry mass were strong for all species, while energy content was comparable to similar species from other parts of the world. These energy content values can serve as standard values to inform bioenergetic models which can be used to explain and predict trends in predator and prey populations under different environmental and management scenarios in southern temperate ecosystems.