Projected costs of future commercial magnetic-fusion reactors and estimates of the related energy costs are useful figures of merit in assessing the attractiveness of magnetic-fusion-energy (MFE) approaches and options in comparison with competitive alternatives, provided “standard” methodologies are used to make meaningful comparisons. The state of current methods and assumptions used in the US and EURATOM MFE studies is summarized, with a view toward facilitating commonality (where appropriate) and noting differences.