The short answer
A blue whale can grow to about 100 feet (30 m) long and weigh more than 330,000 pounds (about 150 metric tons). The biggest ones live around Antarctica. That is about as long as 17 adult men lying head to toe, and as heavy as about 1,650 of them. It is the largest animal known to have ever lived.
- Scientific name
- Balaenoptera musculus
- Length
- Up to about 90 ft (27 m) in the North Atlantic and North Pacific; up to about 110 ft (33.5 m) around Antarctica
- Longest reliable record
- 33.0 m (about 108 ft), measured by whalers in 1930
- Weight
- More than 330,000 lb (about 150 metric tons) for the largest Antarctic whales
- Size at birth
- About 23 ft (7 m) long, 5,000–6,000 lb
- Heart
- About 400 lb (180 kg) in a preserved specimen
- Food
- Krill; the biggest may eat up to 6 tons a day
- Status
- Endangered (IUCN and U.S. Endangered Species Act)
How big is a blue whale?
Blue whales are big in every direction, but the size you’ll see depends on where the whale lives.
NOAA Fisheries, the U.S. government’s ocean wildlife agency, says blue whales in the North Atlantic and North Pacific grow up to about 90 feet and weigh over 100,000 pounds. Around Antarctica, they can reach about 110 feet and more than 330,000 pounds. Females are usually a bit bigger than males.
So when people ask “how big is a blue whale?”, the honest answer is a range. In old whaling records, three out of four blue whales were shorter than about 83 feet (25.3 m). Only a few giants in the Southern Ocean went past 100 feet.
Blue whale length: how long is a blue whale?
You’ll often see “110 feet” or “33.58 meters” given as the record. Here’s the catch: that 1909 whale was measured more than a century ago, and scientists don’t fully trust it.
A 2015 study in the journal PeerJ looked at whaling records for blue whales. It found:
- The longest whale in the International Whaling Commission records was 33.0 m (about 108 ft), caught in Antarctic waters in 1930.
- 88 whales in the records were longer than 30 m (98 ft). All but one came from the Southern Ocean.
- Early lengths over 30.5 m (100 ft) “should be treated with suspicion.” Some early whalers may have measured in Norwegian feet, which are slightly longer than regular feet. They may also have measured the whales in different ways.
- Most caught whales were much smaller: 95% were shorter than 27.1 m (about 89 ft).
So “up to about 100 feet” is a fair everyday answer. “Up to 110 feet” is the top end for rare Antarctic giants.
How much does a blue whale weigh?
Weighing a blue whale is harder than measuring one. According to the 2015 PeerJ review, no complete blue whale has ever been weighed in one piece.
What we have instead:
- NOAA’s figure: more than 330,000 pounds (about 150 metric tons) for the biggest Antarctic whales.
- Whalers’ estimates: the two highest are 190 and 199 metric tons. Whalers cut the whales into pieces, added up how much went into their cooking tanks, then guessed how much blood and fluid was lost. These are estimates, not true weigh-ins.
- Math-based estimates: a 2024 study calculated that the very longest blue whales could have weighed about 270 tons. That number comes from a formula, not a scale.
The old claim that blue whales “weigh up to 200 tons” sits at the very top edge of these estimates. It isn’t a typical weight.
Blue whale size comparison
Numbers this big are hard to picture, so let’s line some things up. The table uses a 100-foot, 330,000-pound blue whale, which is a very large adult.
| Compared with… | Its size | How it stacks up to a 100-ft blue whale |
|---|---|---|
| Average U.S. adult man | 5 ft 9 in tall, 199 lb | About 17 men lying head to toe; about 1,650 men in weight |
| SUE, the largest known T. rex | More than 40 ft long | About 2.5 SUEs nose to tail |
| Asian elephant | 6,000–12,000 lb | About 27 to 55 elephants in weight |
| Newborn blue whale calf | About 23 ft, 5,000–6,000 lb | About 4 calves long |
| Boeing 737-8 airliner | 129 ft 6 in long | The plane is about 30 ft longer |
Comparisons are rounded. Whale figures from NOAA Fisheries and the National Park Service; other lengths and weights from the CDC, Field Museum, Smithsonian’s National Zoo and Boeing (see Sources).
Blue whale size comparison to a human
The average U.S. man is about 5 feet 9 inches tall. You would need about 17 of them lying head to toe to match one 100-foot blue whale. The average U.S. woman is about 5 feet 3.5 inches tall, so it would take about 19 women.
Weight is even more lopsided. A 330,000-pound whale weighs about as much as 1,650 average men (199 pounds each), or about 1,900 average women (172 pounds each).
Even a newborn blue whale is about 23 feet long. That’s roughly four adults lying head to toe. It weighs 5,000 to 6,000 pounds, close to a small adult Asian elephant. The National Park Service says calves can gain more than 250 pounds a day on their mother’s rich milk.
How big is a blue whale’s heart?
You may have heard that a blue whale’s heart is “the size of a car.” The real measurements are still impressive.
In 2014, a blue whale died in the ice off Newfoundland, Canada. The Royal Ontario Museum preserved its heart, and it weighs nearly 400 pounds (about 180 kg). With its big blood vessels attached, it stands about 6.5 feet tall. The museum’s lead preserver said that, when fully stretched open, it could squeeze into a Smart car, one of the smallest cars on the road.
So “car-sized” is a stretch unless you mean a very small car. Still, the museum says the blue whale heart is the largest of any animal on Earth.
Look a little closer
That giant heart beats incredibly slowly. Scientists attached a heart-monitoring tag to a wild blue whale and recorded it on feeding dives as deep as 184 meters (about 600 feet). Underwater, its heart usually beat just 4 to 8 times a minute, and sometimes only 2 times a minute. Back at the surface, it sped up to 25 to 37 beats a minute as the whale caught its breath. That’s close to the fastest scientists think a heart that big can go.
Is the blue whale the biggest animal ever?
NOAA calls blue whales the largest animals ever to live on our planet. That includes every dinosaur we know of.
In 2023, one fossil challenged that title. Scientists described Perucetus colossus, an ancient whale from Peru. They estimated it might have weighed anywhere from 85 to 340 metric tons. In 2024, another team re-ran the numbers and estimated about 60 to 114 tons. They concluded it did not beat today’s blue whales. For now, the blue whale keeps the crown.
Why are blue whales so big?
Blue whales eat tiny shrimp-like animals called krill. Krill gather in huge, dense swarms, but the swarms can be far apart. The PeerJ review explains that a giant body helps a whale travel efficiently between feeding areas. It also stores lots of energy as blubber for long trips. The biggest blue whales may eat up to 6 tons of krill a day, according to NOAA.
Being huge didn’t protect them from people. NOAA says today’s blue whales are only a small fraction of what lived before modern commercial whaling. The IUCN estimates there are about 5,000 to 15,000 adults. They are still Endangered, but NOAA reports that populations are increasing.
Guess first: is the biggest blue whale longer than a Boeing 737 airliner?
No! Even the smallest current 737, the 737-7, is 116 feet 8 inches long. The popular 737-8 is 129 feet 6 inches. The longest reliably measured blue whale was about 108 feet. Even a record-setting whale would fit along the plane’s body with room to spare.
FAQ
How big is a blue whale in feet?
Northern blue whales grow up to about 90 feet. The largest Antarctic blue whales can reach about 100 to 110 feet. In whaling records, 95% of blue whales were under about 89 feet.
How long is a blue whale in meters?
Up to about 27 meters in the Northern Hemisphere and about 33 meters around Antarctica. The longest reliable record is 33.0 meters, measured by whalers in 1930.
How much does a blue whale weigh?
The biggest can weigh more than 330,000 pounds, or about 150 metric tons. Nobody has ever weighed a whole blue whale in one piece, so the heaviest figures (190 to 199 tons) are whalers’ estimates.
How big is a blue whale compared to a human?
A 100-foot blue whale is as long as about 17 average men lying head to toe. It weighs about as much as 1,650 men.
How big is a baby blue whale?
A newborn calf is about 23 feet long and weighs 5,000 to 6,000 pounds. It can gain more than 250 pounds a day while nursing.
Are female blue whales bigger than males?
Yes. As in many baleen whales, female blue whales are generally larger than males, according to NOAA Fisheries.
Keep exploring
Sources
- Blue Whale, NOAA Fisheries — fisheries.noaa.gov/species/blue-whale — lengths by region (about 90 ft vs about 110 ft), weights (over 100,000 lb vs over 330,000 lb), females larger, largest animal ever, up to 6 tons of krill a day, far fewer than before commercial whaling but increasing, Endangered under the ESA.
- McClain, C.R. et al. “Sizing ocean giants: patterns of intraspecific size variation in marine megafauna.” PeerJ, 2015 — doi.org/10.7717/peerj.715 — 33.0 m longest record (1930), 88 whales over 30 m, doubts about the 33.58 m record and pre-1920s measurements, 95% under 27.1 m, no complete whale ever weighed, whalers’ estimates of 190 and 199 t, why blue whales are so large.
- Blue Whale, U.S. National Park Service — nps.gov/places/blue-whale.htm — calf about 23 ft and 5,000–6,000 lb at birth, calves gaining over 250 lb a day.
- “The Painstaking Process of Preserving a 400-Pound Blue Whale Heart,” Smithsonian Magazine, 2017 — smithsonianmag.com/… — Royal Ontario Museum heart: nearly 400 lb, about 6.5 ft tall with vessels, could squeeze into a Smart car when dilated, from a whale that died in ice off Newfoundland in 2014.
- Blue Whale Heart Arrives at the ROM, Royal Ontario Museum — rom.on.ca/news-releases/blue-whale-heart-arrives-rom — the blue whale heart is the largest of any animal on Earth; whales from the North Atlantic population that died in ice in March 2014.
- Goldbogen, J.A. et al. “Extreme bradycardia and tachycardia in the world’s largest animal.” PNAS, 2019 — doi.org/10.1073/pnas.1914273116 — ECG tag on dives to 184 m; diving heart rate 4–8 beats per minute, as low as 2; 25–37 at the surface, near the estimated maximum.
- Bianucci, G. et al. “A heavyweight early whale pushes the boundaries of vertebrate morphology.” Nature, 2023 — doi.org/10.1038/s41586-023-06381-1 — Perucetus colossus mass estimate of 85–340 t.
- Motani, R. & Pyenson, N.D. “Downsizing a heavyweight: factors and methods that revise weight estimates of the giant fossil whale Perucetus colossus.” PeerJ, 2024 — doi.org/10.7717/peerj.16978 — Perucetus revised to about 60–114 t, not heavier than blue whales; about 270 t calculated for the longest blue whales.
- “Balaenoptera musculus (Blue Whale).” IUCN Red List of Threatened Species, 2018 assessment — doi.org/10.2305/IUCN.UK.2018-2.RLTS.T2477A156923585.en — Endangered; about 5,000–15,000 mature individuals; increasing in the Antarctic and North Atlantic.
- Body Measurements, CDC National Center for Health Statistics — cdc.gov/nchs/fastats/body-measurements.htm — average U.S. adult man 68.9 in and 199.0 lb; woman 63.5 in and 171.8 lb.
- SUE the T. rex, Field Museum — fieldmuseum.org/blog/sue-t-rex — SUE is more than 40 ft long and the largest T. rex specimen known.
- Asian Elephant, Smithsonian’s National Zoo and Conservation Biology Institute — nationalzoo.si.edu/animals/asian-elephant — adults weigh 6,000–12,000 lb.
- 737 MAX, Boeing — boeing.com/commercial/737max — 737-7 length 116 ft 8 in; 737-8 length 129 ft 6 in.
Sources checked: 12 September 2026.
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