Do subatomic particles have finite size?

We know atoms are mostly "made" out of empty space, so the nucleus and all the subatomic particle are very small in compared to the magnitude of the atoms. We also know that atoms are incredibly small, so how small are subatomic particle? Can we measure their size?

Is it meaningful to even ask this question?

• "We know atoms are mostly "made" out of empty space" ::grumble:: That statement may be suitable for pop-sci contexts but it is more wrong than right. – dmckee Apr 16 '15 at 0:39
• Related: physics.stackexchange.com/q/41676/2451 and links therein. – Qmechanic Jun 6 '15 at 11:06
• I have written elsewhere about my take on how "size" works in quantum mechanics. The short answer is that the best "size" is probably the wavelength. – rob Jun 7 '15 at 19:22

• Note that nucleons are "subatomic" particles and they certainly are not point particles. The word you want is "fundamental". And the classical electron radius has no meaning whatsoever that can be related to the "size" of the particle which is subject to strong experimental upper bounds on order of $10^{-18}\,\mathrm{m}$. – dmckee Apr 16 '15 at 0:42