By how much does the distance between the earth and sun change?

The aphelion and perihelion distances of the Earth are approximately 152,098,000 and 147,098,000 kilometers, respectively, meaning that there is a 5,000,000-kilometer difference in distance.

This is actually a little bit oversimplified because the Earth's orbit is affected by precession and the gravitational pull of the other planets; for instance, the perihelion distance in 2015 was 147,096,203.90 kilometers, and in 2016 it will be 147,100,175.85 kilometers.

Because of the elliptical nature of Earth's orbit, the distance between the planet and the Sun varies year-round. It is approximately 147 million kilometers at its closest point (perihelion), which falls around early January, and 152 million kilometers at its farthest point (aphelion), which falls around early July. Consequently, the annual variation in the distance between the planet and the Sun is about 5 million kilometers.