It takes the Earth approximately 365.25 days to complete one revolution around the sun. The extra quarter of a day that is gained each year is why a leap year is added to the calendar every four years. The day added in a leap year is February 29.
The Earth orbits the sun in an elliptical path, meaning the distance between the Earth and the sun changes depending on where in the orbit the earth is. When the earth is at its closest point to the sun, the distance between the two is 91.45 billion miles. At the farthest point on the Earth's orbit, the distance grows to 94.56 billion miles apart.