Emperor Penguin Size Comparison: Just How Big and Tall Do They Get?

The emperor penguin (Aptenodytes forsteri) is the world’s heaviest and tallest living penguin species. Read on to find out just how big they can get and how they compare to both other penguins and other heavyweights of the bird world!

Emperor Penguin Size Stats

Adult emperor penguins can grow to 3.7 – 3.8 ft. (1.12 – 1.15 m) tall, making them the tallest of all extant penguins. Their weight fluctuates greatly depending on the season, from a low of 42 lbs. (19 kg) to a high of 101.5 lbs. (46 kg), as both males and females slim down while they are incubating eggs and raising chicks. Even at the low end of their range, however, they are still the heaviest living penguins too.

Emperor Penguins Compared to King Penguins

The king penguin (Aptenodytes patagonicus) is the emperor penguin’s closest living relative and only other member of the Aptenodytes genus. Collectively they are known as the “great penguins.” The king penguin is the second tallest and heaviest penguin, growing up to 3.08 – 3.12 ft. (.94 – .95 m) tall with a weight of between 20 – 33 lbs. (9 – 15 kg). As seen in the lineup above, however, the emperor penguin is still literally head and shoulders above its closest competition!

Emperor Penguins Compared to Little Penguins

The world’s smallest penguin is the fittingly named little penguin (Eudyptula minor). It only grows to 15.8 – 17.7 in. (40 – 45 cm) tall and weighs between 1.1 – 4.6 lbs. (0.5 – 2.1 kg). This means the emperor penguin is over 2.5 times as tall as its smallest penguin cousin. Even more impressive, at both their maximum weights, the emperor is nearly 22 times as heavy! (The “little blue” can be seen all the way at the end on the right in the lineup photo.)

Emperor Penguins – One of the Heavyweights of the Bird World!

Emperor penguins are not only the world’s heaviest penguins, they are one of the heaviest living birds overall. As seen on the top ten list below, the only ones who weigh more are five of the larger ratites, including two ostriches (Struthio spp.), two cassowaries (Casuarius spp.), and the emu (Dromaius novaehollandiae). While these and many other birds are much taller, emperor penguins are proportionally heavier. This is thanks to the combination of their special adaptations of solid bones, dense feathers, and thick insulating fat layer. The rest of the top ten list is rounded out by three more ratites, including another cassowary and two rheas (Rhea spp.)…and the king penguin!

Top Ten Heaviest Living Birds (Ranked By Maximum Weight/Mass)