Bulk Modulus Calculator

The Physics of Compression

If you take a block of steel and drop it to the bottom of the Mariana Trench, the immense hydrostatic pressure of the deep ocean will push in on the steel from every possible direction simultaneously.

Does the steel block shrink? Yes, but only microscopically.

The Bulk Modulus ($K$) measures a substance's resistance to uniform, all-around compression.

• A High Bulk Modulus means the substance is nearly incompressible (like liquid water or solid steel).
• A Low Bulk Modulus means the substance is easily squished into a smaller volume (like a balloon filled with air).

The Equation

The formula calculates the ratio of the pressure you applied versus the physical percentage of volume that the object lost.

Note the negative sign in the equation! Because compressing an object causes its volume to decrease (making $\Delta V$ a negative number), the extra negative sign flips the final result so that the Bulk Modulus is always a positive value.