By Chance E. Gartneer | Updated March 24, 2022

In many scientific and engineering contexts, you’ll need to know a sphere’s weight without a scale. By combining the sphere’s geometry with its material density, you can compute its mass directly.

Step 1 – Calculate the Volume

Cube the radius and multiply by 4/3 π to get the volume. For a sphere with a 10 cm radius, the calculation is:

Volume = 4/3 π × 10³ cm³ ≈ 4 188.79 cm³

Step 2 – Identify the Density

Determine the material’s density. In this example we’ll use 100 mg cm⁻³.

Step 3 – Compute the Weight

Multiply the volume by the density:

Weight = 4 188.79 cm³ × 100 mg cm⁻³ ≈ 418 879 mg

TL;DR

Small, real spheres can also be weighed on a conventional balance, but the volume‑density method works for any size or material.