The commonly used equation to determine Liver iron concentration (LIC) from R2* was developed from a very small cohort (n=23) and an acquisition approach significantly different to that currently used in clinic. Three subsequent calibrations used progressively larger moderate (n=43-88) to derive divergent results. This study measured liver R2* from 835 gradient echo relaxometry acquisitions in 167 clinical examinations. Correlation between R2* and reference LIC measurement was evaluated for first to third order polynomials. A linear equation provided the best fit, delivering a new calibration equation that differs significantly from earlier work.