NASA
PerplexingPotato / imgur.com
Here's the maths:
Earth-moon distance (384,440km) – [diameter of Mercury (4879km) + diameter of Venus (12,104km) + diameter of Mars (6771km) + diameter of Jupiter (138,350km) + diameter of Saturn (114,630km) + diameter of Uranus (50,532km) + diameter of Neptune (49,105km)] = 8069km.
Check with Wolfram Alpha if you don't trust us (they work it out as 8031km). The calculation uses the average distance between the Earth and moon, and the average diameters of each of the planets.