There has been a lot of recent debate about what is middle income – but the range of ‘middles’ that can be derived from earnings and income data is potentially confusing. This briefing note attempts to provide some clarity, by detailing the relative merits and drawbacks of different approaches and sets out how a wide range of possible middles can be derived. There is no definitive answer to the question of which middle is ‘best’ – but it is certainly the case that looking at overall income and adjusting for the size and composition of households (‘equivilising’), helps compare real living standards. Focused on low to middle earners, the Resolution Foundation uses an equivalised working-age household income of £30,000 to define its ‘middle’.