Let’s see how far away Uranus is from the Earth. First consider the fact that both Earth and Uranus are orbiting the Sun. This means that the distance between them can change, depending on their relatively positions in the Solar System.
The closest Uranus can get to Earth is 2.57 billion km.
Imagine Earth, Uranus and the Sun are all in straight line. When Uranus is at its closest point to Earth, the three objects are lined up with the Sun, Earth and Uranus. This is when Uranus is a mere 2.57 billion km. But Earth and Uranus are located on opposite sides of the Sun, they’re at their most distant point. When this happens, they’re 3.15 billion km.
We have recorded an episode of Astronomy Cast just about Uranus. You can access it here: Episode 62: Uranus.