How big is Space Needle?
Space Needle: 184 m (604 ft). Measured as height — overall height (605 ft).
Source: Wikipedia — Space Needle
Where it sits
Among the 23 buildings & towers on this page Space Needle ranks 16th from the top by size. The largest in the group is Burj Khalifa at 828 m, which is 4.5× the size of Space Needle, while the smallest, Christ the Redeemer, is 30 m.
Stand an adult of 1.7 m beside it and the ratio is 108×: you would need 108 people stacked head to foot to match its size.
In everyday distances
A football pitch is about 105 m long. Space Needle is 1.75× that, which puts it at 1.8 pitch lengths from end to end.
Walking at an easy 1.4 m/s you cover 184 m in 2.2 minutes. A jet at 900 km/h covers it in 736 milliseconds.
Next to its neighbours in size
The nearest thing larger than it in this collection is RMS Titanic at 269 m (883 ft), 1.46× the size. Note the two figures are not the same measurement: for Space Needle it is height, for RMS Titanic it is length.
The nearest thing smaller is Statue of Unity at 182 m (597 ft), so Space Needle is 1.01× as big as it. They sit in the same group.
Against fixed yardsticks
Against three fixed yardsticks — Eiffel Tower (330 m) is 1.79× the size of Space Needle; Space Needle is 6.15× the size of blue whale (29.9 m); Earth (12,742 km) is 69,250× the size of Space Needle.
How this figure was taken
Building heights depend on the rule used: architectural height counts spires but not antennas, tip height counts everything. The basis is named with each figure.
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 the Space Needle?
184 m (604 ft), measured as height: overall height (605 ft).
Where does the Space Needle rank among buildings & towers?
Number 16 of 23 on this site, from Burj Khalifa at 828 m down to Christ the Redeemer at 30 m.
What is the next size up?
RMS Titanic, at 269 m, is 1.46× the size.
What is the next size down?
Statue of Unity, at 182 m, is 1.01× smaller.
How reliable is the figure?
It is taken from the cited Wikipedia article and states its basis (overall height (605 ft)). Values are rounded, and where individuals differ the figure is a representative one, so expect small differences from other sources.