比模量是单位密度的弹性模量，是一种材料性质。又称劲度－质量比或比劲度。比模量高的材料在航天工业中有广泛应用，这个领域需要把质量降至最低。从因次分析可得，比模量的单位为距离的平方除以时间的平方。

Specific modulus is a materials property consisting of the elastic modulus per mass density of a material. It is also known as the stiffness to weight ratio or specific stiffness. High specific modulus materials find wide application in aerospace applications where minimum structural weight is required. The dimensional analysis yields units of distance squared per time squared.