Soil nitrogen mineralisation (N ), the conversion of organic into inorganic N, is important for productivity and nutrient cycling. The balance between mineralisation and immobilisation (net N ) varies with soil properties and climate. However, because most global-scale assessments of net N are laboratory-based, its regulation under field-conditions and implications for real-world soil functioning remain uncertain. Here, we explore the drivers of realised (field) and potential (laboratory) soil net N across 30 grasslands worldwide. We find that realised N is largely explained by temperature of the wettest quarter, microbial biomass, clay content and bulk density. Potential N only weakly correlates with realised N , but contributes to explain realised net N when combined with soil and climatic variables. We provide novel insights of global realised soil net N and show that potential soil net N data available in the literature could be parameterised with soil and climate data to better predict realised N .