150 t331,000 lb
A large adult blue whale weighs about 150 tonnes (roughly 330,000 lb), as much as about 30 African elephants. Many adults are lighter, especially pygmy and Northern Hemisphere blue whales. The heaviest one ever recorded, a pregnant female caught in the Southern Ocean in 1947, weighed 190 tonnes (about 419,000 lb).
| Heaviest ever recordedA 27.6 m pregnant female, Southern Ocean, 1947 | 190 t419,000 lb |
|---|---|
| Large adultAbout 27 m (89 ft) long | 150 t331,000 lb |
| Pygmy blue whale, adult femaleCalculated average; males about 75 t | 90 t198,000 lb |
| Calf at weaningAbout 7 months old | 20 t44,100 lb |
| Newborn calfUsually 2 to 3 tonnes | 2.5 t5,510 lb |
It depends on where the whale lives and how long it is. NOAA Fisheries gives Antarctic blue whales, the biggest population, a maximum of about 110 ft (33 m) and 330,000 lb (150 t). Blue whales in the North Atlantic and North Pacific are smaller, reaching about 90 ft (27 m). In every population, females are generally larger than males.
Weight climbs steeply with length. A 2025 study by Gregory Paul and Asier Larramendi puts a 27 m (89 ft) blue whale at about 150 tonnes, and a 27 m whale cut up and weighed by Japanese whalers came to about 139 t once its lost blood was added back. In the Southern Hemisphere, females reach maturity at about 23 to 24 m and males at about 22 m, so plenty of adults weigh well under 150 t.
Pygmy blue whales, found mainly in the southern Indian Ocean and off Australia, are the smallest subspecies. They grow to about 24 m, and their calculated average weight is roughly 75 t for males and 90 t for females.
No scale can lift a blue whale, so every real weight comes from the whaling era, when carcasses were cut into pieces and each piece was weighed. One well-documented case, written up by Winston in 1950, was a 27.1 m female that came to at least 136.4 tonnes.
Piecemeal weighing always loses blood and other fluids, so these figures are a bit low. Recent studies add back about 7 to 14% of the weight to allow for it. For living whales, and for the very biggest ones that were never weighed, weight is estimated from length using formulas built on those old records.
The heaviest blue whale on record weighed 190 tonnes (418,878 lb). She was a 27.6 m (90 ft 6 in) female caught in the Southern Ocean on 20 March 1947, and she was pregnant and unusually fat, which explains the high weight for her length.
She was not the biggest blue whale ever measured. A female landed at the Grytviken whaling station in South Georgia in 1909 measured about 33.5 m (110 ft), but her weight was never recorded. Estimates for a 33 m whale disagree: Ryosuke Motani and Nicholas Pyenson (2024) get about 250 to 270 t, while Paul and Larramendi (2025) argue blue whales probably never topped about 200 t. So the true maximum is uncertain, but the largest females were almost certainly heavier than 190 t.
Almost certainly yes. In 2023, scientists described Perucetus colossus, a 39-million-year-old whale from Peru with extremely thick, heavy bones, and estimated it at 85 to 340 tonnes, which would have put it in blue whale range or above. The estimate came from only part of one skeleton.
Later studies cut it down sharply. Motani and Pyenson (2024) estimated 60 to 70 t at 17 m long, and no more than about 114 t even at 20 m. Paul and Larramendi (2025) went lower still, to 35 to 40 t. Guinness World Records still lists the two jointly as the heaviest animal ever, but on current evidence the blue whale holds the title on its own.
A large adult weighs about 330,000 lb (150 t). The heaviest one ever recorded weighed 418,878 lb, and a newborn calf weighs about 4,400 to 6,600 lb.
A newborn blue whale is 6 to 8 m long and weighs 2 to 3 tonnes (4,400 to 6,600 lb). It drinks about 200 litres of milk a day and gains up to 90 kg (198 lb) daily, reaching about 20 tonnes by the time it is weaned at around 7 months.
The only blue whale heart ever preserved, from a whale that washed ashore in Newfoundland in 2014, weighed more than 180 kg (about 400 lb) even after it was drained of blood. It measured about 1.5 m by 1.5 m and is now on display at the Royal Ontario Museum in Toronto.
According to Guinness World Records, a blue whale’s tongue typically weighs about 4 tonnes (8,818 lb), similar to a whole adult elephant. It is the heaviest tongue of any animal.
A pregnant female caught in the Southern Ocean in March 1947 weighed 190 tonnes. Longer blue whales have been measured, up to about 33.5 m, but none of them was weighed.
Last checked October 3, 2026.
