How long did it take for Jupiter to form?
Jupiter formed in no more than a few million years.
Jupiter is a large planet which is mainly Hydrogen and Helium. It formed from a disk of gas and dust as did the rest of the planets.
Unlike rocky planets, Jupiter had to form quickly. The reason for this is that Hydrogen dissipates quite quickly. The solar wind would tend to push any Hydrogen further and further away from the Sun. It is thought that Jupiter had a maximum of about 4 million years to form.