Emission norms are becoming more stringent over the years due to environmental and health concerns raised across the globe1.  Particulate Number (PN) emission limit is introduced for EU Stage V non-road applications, coming into force by 2019 along with Particulate Matter (PM) for diesel engines. Diesel Particulate Filter (DPF) is a best available technology to meet Tail Pipe (TP) PN limits (1E12 particles/kWh @19-560kW) for off high way applications. It is learnt that the main challenge to meet PN limits is to understand soot cake internal characteristics during soot regeneration and loading2. Also, DPF performance is sensitive to cold start, fast warm-up and rapid fluctuations in engine speed/load conditions3. It involves significant cost and test bed time to understand DPF performance at this microlevel over entire engine speed/load operation. In order to address this issue DPF semi physics-empirical model is developed to predict influence of these factors on TP PN for diesel engines. The empirical model is able to identify engine speed/loads with high PN and engine calibration is altered to mitigate PN emission limit the risk.