How big is Jupiter?
Jupiter: 142,984 km (469,107,612 ft). Measured as diameter — equatorial diameter.
Source: Wikipedia — Jupiter
Where it sits
Among the 16 planets & moons on this page Jupiter ranks 2nd from the top by size. The largest in the group is the Sun at 1,392,700 km, which is 9.74× the size of Jupiter, while the smallest, Ceres, is 939 km.
Stand an adult of 1.7 m beside it and the ratio is 84,108,235×: you would need 84,108,235 people stacked head to foot to match its width — roughly a crowd the size of a small town standing on each other.
In everyday distances
A football pitch is about 105 m long. Jupiter is 1,361,752× that, which puts it at 1,361,752 pitch lengths from end to end.
Light covers its diameter in 477 milliseconds. A jet cruising at 900 km/h would need 6.6 days to fly the same distance in a straight line.
Next to its neighbours in size
The nearest thing larger than it in this collection is the Sun at 1,392,700 km (4,569,225,722 ft), 9.74× the size. Both figures are the same kind of measurement, so the gap is a fair one.
The nearest thing smaller is Saturn at 120,536 km (395,459,318 ft), so Jupiter is 1.19× as big as it. They sit in the same group.
Against fixed yardsticks
Against three fixed yardsticks — Jupiter is 433,285× the size of Eiffel Tower (330 m); Jupiter is 4,782,074× the size of blue whale (29.9 m); Jupiter is 11.2× the size of Earth (12,742 km).
How this figure was taken
Worlds are listed by diameter. Gas giants are not round, so equatorial diameter is used for them and mean diameter for the rest. All figures are rounded from published mission data.
How the sizes are taken. Each figure says what it measures — height, length, diameter or elevation — and for which individual or convention. Everything is drawn standing upright on one baseline so a single scale holds, including things that are long rather than tall. Values come from the linked Wikipedia article for each item.
Read the rest — common questions
How big is Jupiter?
142,984 km (469,107,612 ft), measured as diameter: equatorial diameter.
Where does Jupiter rank among planets & moons?
Number 2 of 16 on this site, from the Sun at 1,392,700 km down to Ceres at 939 km.
What is the next size up?
The Sun, at 1,392,700 km, is 9.74× the size.
What is the next size down?
Saturn, at 120,536 km, is 1.19× smaller.
How reliable is the figure?
It is taken from the cited Wikipedia article and states its basis (equatorial diameter). Values are rounded, and where individuals differ the figure is a representative one, so expect small differences from other sources.