How much does a blue whale weigh at birth?

Blue Whale Females give birth to a single calf every two or three years following a 12-month gestation. Blue whale calves measure about 7 m (23 ft.) and 2,700 to 3,600 kg (6,000-8,000 lb.). Calves are weaned at eight months, when they gain as much as 90 kg (200 lb.) a day.
---Refer https://en.wikipedia.org/wiki/Blue_whale#Life_history

Additional INFO: The largest of all known animals, the blue whale attains a maximum length and weight of about 30 metres (100 feet) and 150 {tons;} the largest known individual, a female 33.58 metres (110.14 feet) in length, was reported in 1922.---encyclopaedia britannica online

When born, the blue whale calf is about 23 feet (7 m) long and weighs 5,000 to 6,000 pounds (2,700 kg).

Gestation lasts 10 to 12 months and the average calf is 23 feet long and weighs 4,440 pounds at birth.

Calves are 23 to 27 feet (7-8.2 m) long at birth and 3 tons (2,722 kg).

https://www.marinemammalcenter.org/animal-care/learn-about-marine-mammals/cetaceans/blue-whale