South Africa is considering introducing a universal health care system. A key concern for policy-makers and the general public is whether or not this reform is affordable. Modelling the resource and revenue generation requirements of alternative reform options is critical to inform decision-making. This paper considers three reform scenarios: universal coverage funded by increased allocations to health from general tax and additional dedicated taxes; an alternative reform option of extending private health insurance coverage to all formal sector workers and their dependants with the remainder using tax-funded services; and maintaining the status quo. Each scenario was modelled over a 15-year period using a spreadsheet model. Statistical analyses were also undertaken to evaluate the impact of options on the distribution of health care financing burden and benefits from using health services across socio-economic groups. Universal coverage would result in total health care spending levels equivalent to 8.6% of gross domestic product (GDP), which is comparable to current spending levels. It is lower than the status quo option (9.5% of GDP) and far lower than the option of expanding private insurance cover (over 13% of GDP). However, public funding of health services would have to increase substantially. Despite this, universal coverage would result in the most progressive financing system if the additional public funding requirements are generated through a surcharge on taxable income (but not if VAT is increased). The extended private insurance scheme option would be the least progressive and would impose a very high payment burden; total health care payments on average would be 10.7% of household consumption expenditure compared with the universal coverage (6.7%) and status quo (7.5%) options. The least pro-rich distribution of service benefits would be achieved under universal coverage. Universal coverage is affordable and would promote health system equity, but needs careful design to ensure its long-term sustainability.