Vulnerability to climate-induced rainfall extremes and the absence of a standardized national design rainfall estimation framework in Bangladesh pose challenges to water infrastructure planning and design. This paper introduces the development of a national-scale Design Rainfall Estimation Tool tailored to the deltaic and monsoonal characteristics of Bangladesh. Leveraging Australia’s established Intensity-Duration-Frequency (IDF) framework in the Australian Rainfall and Runoff (ARR) guidelines, this paper explores how a design rainfall portal can be developed for Bangladesh like Australia. Programming and statistical tools such as Python and R, combined with GIS-based geospatial analytics, will underpin this software. Validation against recorded rainfall data will be made to ensure the accuracy of the proposed software. The resulting system aims to support adaptive infrastructure design, improve flood resilience and inform national water policy to reduce flood damage in Bangladesh. The proposed IDF software will enable planners and engineers of Bangladesh to access climate change sensitive design rainfall estimates at any location in Bangladesh by inputting latitude and longitude, like Australian IDF portal. The study is being continued and it is expected the proposed software will be ready in a few years’ time.