The need for conservation action to be cost-effective is widely accepted and this has prompted an increased interest and effort to assess effectiveness. Assessing financial costs of conservation is equally important, yet its measurement and assessment are repeatedly identified as lacking. The healthcare sector however, has made substantial progress in identifying and including costs in decision-making. Here, we consider what conservation can learn from this experience. We present a three-step framework for identifying and recording the relevant financial costs and benefits of conservation interventions where the user 1) describes the costing context, 2) determines which types of cost and benefit to include and 3) obtains values for these costs and benefits alongside metadata necessary for others to interpret the data. This framework is designed to help estimate economic costs, but can also be used flexibly to record direct costs of interventions (i.e. accounting costs), calculate financial benefits, and calculate cost effectiveness. Although recording cost data can be deceptively complex, this framework facilitates the improved recording of financial costs and benefits, and shows how this could enhance the assessment of cost-effectiveness across a broad range of conservation contexts.