The Agronomic Ex Ante Explorer is a tool designed to enable users to develop a reasonable starting point for structured ex ante estimates of potential beneficiaries and benefits to a prospective agronomy investment, in cases where limited data resources are available for more comprehensive and rigorous ex ante evaluations. It is not intended to obviate more rigorous analysis, where data enable such work. However, it may be a useful tool for assembling some initial estimates of the potential number of beneficiaries of an agronomy project focused on a particular crop and geography, as well as offering a structured way to make underlying assumptions (e.g., on adoption rates, yield gains to adoption) explicit.