Achieving a number of Sustainable Development Goals (SDGs) depends on increasing the stock of natural capital. This working paper presents the methodology of how to estimate the “natural capital gap” -- the difference between the level of such capital now and the amount that will be needed to meet the SDGs. The paper also reports the results of an initial investigation of the link between the SDGs and the natural capital requirements, particularly natural capital-relevant SDGs and their targets, such as SDG 2 (hunger), SDG3 (healthy lives) SDG 6 (water and sanitation), SDG 11 (resilient cities), SDG 12 (sustainable consumption and production), SDG 13 (climate change), SDG 14 (marine ecosystems) and SDG 15 (terrestrial ecosystems). It reveals that the sum of the natural capital gap is estimated at between $31.9 and $86.9 trillion, with the largest uncertainties arising from the value of remediating land, reducing forest loss and reducing loss of wetlands. If compared with the estimate of the current stock of natural capital by the World Bank, about $105 trillion globally, this analysis suggests that meeting these SDGs could enhance that stock by between 30% and 83%.