OBJECTIVES: When developing a budget impact model (BIM) the design stage is key. A particular element which should be carefully considered during the design phase is the perspective and in particular who the audience will be. The objective of this study was to identify who the potential users and healthcare decision-makers may be and what elements should be captured within the BIM to meet their requirements within a UK setting. METHODS: Research was conducted in a staged approach. The first stage involved identifying the different types of potential users of a BIM. Following identification of these different users, the next stage of research sought to identify the cost criteria each user is expected to assess a BIM against, thus informing what should be captured in an analysis. The final stage then identified what cost categories are required in a BIM to satisfy these criteria. RESULTS: Two main users of a BIM were identified: providers and commissioners. The criteria that a provider is expected to consider is: what is the incremental cost and resource use implications of providing the intervention in question? What is the incremental income that will be received for providing this intervention? Whereas, the criteria that a commissioner is expected to consider are: what is the incremental cost of commissioning the provision of the intervention? Is there any added value in terms of quality, capacity or outcomes? An example of appropriate costs which are aligned with the perspective of a provider and commissioner, would be NHS reference costs and national tariffs, respectively.  CONCLUSIONS: Determining the audience of a BIM is crucial in designing a model fit for purpose. Key requirements of a BIM will be dependent on the audience, in particular capturing costs appropriately. Research should be conducted for other countries.