How big is Blue whale?
Blue whale: 29.9 m (98.1 ft). Measured as length — the longest reliably measured individual.
Source: Wikipedia — Blue whale
Where it sits
Among the 23 animals on this page blue whale ranks 1st from the top by size. Nothing else in its group is bigger here, and the smallest, honey bee at 13 mm, is 2,300× smaller.
Stand an adult of 1.7 m beside it and the ratio is 17.6×: you would need 17 people stacked head to foot to match its size.
In everyday distances
It fits inside a football pitch 3.5 times over — a pitch is about 105 m and blue whale is only 29.9 m.
Walking at an easy 1.4 m/s you cover 29.9 m in 21 seconds. A jet at 900 km/h covers it in 120 milliseconds.
Next to its neighbours in size
The nearest thing larger than it in this collection is Christ the Redeemer at 30 m (98.4 ft), 1× the size. Note the two figures are not the same measurement: for blue whale it is length, for Christ the Redeemer it is height.
The nearest thing smaller is whale shark at 18.8 m (61.7 ft), so blue whale is 1.59× as big as it. They sit in the same group.
Against fixed yardsticks
Against three fixed yardsticks — Eiffel Tower (330 m) is 11× the size of blue whale; Earth (12,742 km) is 426,154× the size of blue whale.
How this figure was taken
Animal sizes vary from one individual to the next, so each figure says which individual or average it describes. Heights are taken at the shoulder or standing; lengths run nose to tail tip unless stated.
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 blue whale?
29.9 m (98.1 ft), measured as length: the longest reliably measured individual.
Where does the blue whale rank among animals?
Number 1 of 23 on this site, from blue whale at 29.9 m down to honey bee at 13 mm.
What is the next size up?
Christ the Redeemer, at 30 m, is 1× the size.
What is the next size down?
Whale shark, at 18.8 m, is 1.59× smaller.
How reliable is the figure?
It is taken from the cited Wikipedia article and states its basis (the longest reliably measured individual). Values are rounded, and where individuals differ the figure is a representative one, so expect small differences from other sources.