129 kg285 lb
Doraemon weighs 129.3 kg (285.1 lb), according to his official profile. It is the same number as his height, 129.3 cm (4 ft 3 in), and his chest, 129.3 cm round. The figure was set in 1975 and has never changed, even though the manga often shows Nobita lifting him like a child.
Doraemon’s measurements were fixed around February 1975 by his creator, Fujiko F. Fujio, and his assistant Yoji Katakura, and printed in a “Doraemon encyclopedia” feature in Shogakukan’s Shogaku Yonensei (Fourth Grade) magazine. Height and weight were both set at 129.3, and Shogakukan’s official Doraemon Channel still gives 129.3 cm and 129.3 kg today.
The usual explanation is that 129.3 cm was the average height of a fourth grader at the time, so Doraemon would stand eye to eye with the magazine’s readers. A former Fujiko assistant, Takeshi Ebihara, tells a different story: the birthday, 3 September, came from fellow assistant Rui Hanaka, and 129.3 grew from that. The birth date, 3 September 2112, contains the same digits: 12, 9, 3.
The number turns up all over his profile. His chest and head are both 129.3 cm round, his feet are 129.3 mm long and he has 129.3 horsepower. When he sees a mouse he jumps 129.3 cm in the air and runs away at 129.3 km/h (about 80 mph), against a normal 12 km/h. The Doraemon Channel notes that a chest as big as his height makes him a remarkably cylindrical robot.
Less than you might think. Take his profile literally and treat him as a solid cylinder 129.3 cm tall and 129.3 cm round. That cylinder is 41 cm across and holds π × 20.6 cm × 20.6 cm × 129.3 cm, about 172 litres. Filled with water it would weigh 172 kg; made of solid steel, about 1,350 kg. This is our own rough maths, not an official figure.
At 129.3 kg, Doraemon averages at least 0.75 kg per litre, and more than that if you allow for his round head and short legs. That puts him close to the density of a person, about 1 kg per litre, and nowhere near solid metal. So he is heavy because he is a chunky, child-sized machine, not because he is packed with steel.
He also runs on ordinary food. Japanese reference books describe a stomach called the “atomic furnace” that breaks food down into energy with 100% efficiency, so he eats what people eat (dorayaki above all), and he is not nuclear powered. An anti-gravity device keeps him floating 2 to 3 mm off the ground, which is why his feet never get dirty.
The stories rarely treat him as a 129 kg robot. In the manga Nobita picks him up, Doraemon sits on Nobita’s head, the two wrestle as equals, and in the film Doraemon Comes Back (1998) they ride a seesaw together. His 129.3 horsepower works the other way: he lifts cars, desks and giant gadgets with ease.
One anime episode does use the number. In “Doraemon Goes on a Diet!?”, shown in November 2024, he goes through a slimming tunnel the wrong way, balloons from 129.3 kg to 200 kg, and sets out to lose 70 kg to get back to normal.
Doraemon weighs 285.1 lb, which is 129.3 kg, or a little over 20 stone.
He is 129.3 cm tall, about 4 ft 3 in, the same number as his weight. His sitting height is listed as 100 cm.
His younger sister Dorami is 100 cm tall and weighs 91 kg (about 201 lb), 38 kg less than Doraemon. That weight comes from a 1986 Doraemon gadget catalogue; earlier, a 1980 anime special gave her 35 kg. She is also far stronger, at 10,000 horsepower.
No. His “atomic furnace” is a stomach that turns food into energy. He eats normal food, and his favourite is dorayaki.
The number was chosen in 1975, reportedly because 129.3 cm was the average height of a fourth grader, the readers of the magazine that first printed his profile. It was then reused for his weight, chest, power, jump and running speed.
Last checked October 2, 2026.
