How far is Neptune from Earth?

The distance varies between 4.3 and 4.7 billion kilometers. Neptune is about 30 times farther from the Sun than Earth, and is the outermost of the 8 major planets.

When the Earth is on the same side of the sun as Neptune, the distance to Neptune is shorter than the distance when the Earth is on the opposite side of the sun from Neptune. The distance also changes because both planets revolve round the sun in ellipses, so their distance from the Sun varies. The distance of the Earth from the Sun varies from about 147.1 million kilometers to 152.1 million kilometers. The distance of Neptune from the Sun varies from 4.45 billion km to 4.55 billion km.

Therefore if the earth was on the opposite side of the sun from Neptune, at its maximum distance from the Sun, and Neptune was also at its maximum distance from the sun, the maximum distance of Neptune from Earth would be 4702 million km (or 4.702 billion km).

If the earth was on the same side of the Sun as Neptune, at its maximum distance from the Sun (ie its nearest distance to Neptune) and Neptune was also at its minimum distance from the sun (ie, its nearest distance to earth), the minimum distance of Neptune from Earth would be 4298 million km (or 4.298 billion km). This is a variation of about 9%.

The average distance is 4564 million km or 4.564 billion kilometers (2.835 billion miles).

In other units, this distance would be 30.5 AU or 4.22 light hours or 0.000482 light years.