The impact of disability on people’s lives is often underestimated because the extra costs of living with a disability are not accounted for. This paper analyzes several different methodologies for estimating those costs and explores their usefulness in designing inclusive social policies. For example, one approach is to measure what is currently being spent, while another is to estimate what would need to be spent for equal participation. These can be measured using statistical techniques or through a more qualitative methodology. Each of these methods has its advantages and disadvantages. The paper concludes with recommendations for which methodology fits which purpose, and how they can be used together to obtain a full accounting of the extra costs incurred by people with disabilities.