Petameter to Femtometer

The femtometer is a unit of length equal to 10⁻¹⁵ meters, commonly used to measure the size of atomic nuclei.

1 fm = 10⁻¹⁵ m = 1,000 am = 10⁻⁶ nm. One meter equals 10¹⁵ femtometers.

To convert fm to meters: multiply by 10⁻¹⁵. To convert meters to fm: multiply by 10¹⁵.

Describing the size of protons (~0.87 fm radius) and nuclear diameters (1–15 fm depending on the element).

A proton's charge radius is approximately 0.87 fm. The diameter of a uranium-238 nucleus is about 15 fm.

Confusing femtometers with nanometers — a femtometer is one million times smaller than a nanometer.

Remember: atoms are ~0.1 nm, but nuclei are ~1–10 fm — nuclei are about 100,000 times smaller than the whole atom.