Jupiter is 588 million kilometres from Earth. For comparison, Earth is ‘only’ about 150 million kilometres from the Sun. A space probe called Juno recently arrived at Jupiter to look at its atmosphere, and it took five years to get there!!
As all the planets are on orbits around the sun at different speeds and different distances it is natural for the distances between the planets to change. Lucy is right that at our closest distance when we are closely aligned it is 588 million kilometers but at the most distant points in their orbit it can be 988 million kilometers
Its actually why it takes such a long time to get space craft to planets as they can’t travel in a straight line as the planets orbit the sun. They have to do a kind of spiral orbit to the planet and all the time the planets are still moving.
It is also why the planets appear to wander quite a lot in the sky when we watch them. After all they are named planets as it comes from the latin name planeta which mean wandering star.
Right now (15/03/17 14:48) Jupiter is 680.5 million km from Earth!! We are getting closer to Jupiter every moment but on April 8 we will start to move away again.
Check this out: https://theskylive.com/jupiter-info