Both facial width-to-height ratio (fWHR) and body mass index (BMI) have been associated with aggressive behavior in women but how they influence perception of their potential threat remain unclear. Here, we assessed the effects of fWHR and BMI on perceived formidability from faces of 42 female Ultimate Fighting Championship (UFC) fighters. In study 1, BMI, but not fWHR, positively predicted participants' ratings of aggressiveness and fighting ability from facial photographs. In study 2, both high fWHR and high BMI composite faces were rated as more aggressive, tougher, and more likely to win a fight than low fWHR and low BMI composite faces, respectively. Further analyses revealed that the high BMI composite face was rated as more aggressive and tougher than the high fWHR composite face. Taken together, these results suggest that compared to fWHR, BMI may be a more salient cue to women's formidability.