Carbon stock is calculated from the measured total organic carbon (%) in the soil, and is used as the base measurement in soil carbon accounting. In order to calculate carbon stock, it is necessary to know the soils bulk density (view factsheet) and account for any gravel that might have been present prior to sieving in preparation for analysis.

The final carbon stock value is measured in tonnes per hectare (t/ha) and is a tangible value that can be used in soil carbon models to determine a soils capacity for carbon sequestration. It also provides landholders the ability to calculate total soil carbon storage on their property.