In May 2011, Britain's Conservative/Liberal Democrat coalition government published proposals for reform of the House of Lords. In a White Paper and draft bill they set out detailed plans for a largely or wholly elected second chamber. These marked the latest stage in a long-running debate on Lords reform. The government's proposals aim to change the composition of the second chamber, suggesting that there will be no change to its powers or the conventions governing relations with the House of Commons. But this expectation has been disputed. The House of Lords presently does not make full use of its powers, and many anticipate that it would if its members became elected. This paper reviews the composition of all second chambers internationally, showing that wholly directly elected chambers make up the minority, and that both mixed chambers and indirect election are common. It then reviews the formal powers of all largely and wholly elected chambers. This shows that amongst parliamentary systems the formal powers of the House of Lords are relatively great. But second chamber powers, as well as their composition, vary widely.