<p>As the global deployment of lithium-ion batteries (LIBs) accelerates, efficient and cost-effective recycling strategies are becoming critical to ensure material circularity and supply security. However, although the technical principles of LIB recycling are broadly understood, the economic modelling of recycling processes remains fragmented. In this Review, we examine how recycling costs are assessed across pyrometallurgical, hydrometallurgical and direct recycling routes. Profit margins can vary from US$0.4–3.3 kg⁻¹ (hydrometallurgy) and US$0.5–4.0 kg⁻¹ (pyrometallurgy) to US$2.0–14.4 kg⁻¹ (direct recycling), depending on the process conditions, the cost categories considered and the number and type of recovered products. Models reflect the battery chemistry, scale and regional context. However, many models omit key cost elements such as transport, disassembly or capital expenditures, leading to a general underestimation of costs. These modelling inconsistencies hinder comparability and might misrepresent the economic potential of emerging technologies. Thus, more transparent, geographically diverse and scale-sensitive cost assessments are needed to guide future research and support informed decision-making in industry and policy, especially in light of evolving battery chemistries and regulatory demands.</p>