All things · Inside the Nucleus

Quark (upper limit): how big is it?

Quark (upper limit) is about 1.0 × 10⁻¹⁸ m. In everyday terms, that is ≈ 106 million times smaller than a hydrogen atom.

Size

1.0 × 10⁻¹⁸ m

In metres

1.00 × 10⁻¹⁸ m

Everyday comparison

≈ 106 million times smaller than a hydrogen atom

Chapter

Inside the Nucleus

Did you know?

Quarks are the building blocks of protons and neutrons. Experiments show they're smaller than this — they may have no size at all.

How it compares

• About 63,000 trillion× bigger than Planck length (1.6 × 10⁻³⁵ m).
• About 1,700× smaller than Proton (1.7 fm).

Other things of a similar size

• Proton 1.7 fm
• Helium nucleus 3.4 fm
• Uranium nucleus 15 fm
• Hydrogen atom 106 pm
• Water molecule 275 pm
• Gold atom 288 pm

Sizes are rounded, typical values drawn from standard reference sources, including NIST/CODATA physical constants and NASA's planetary fact sheets. Real objects vary; see About for how sizes are chosen.