Nikon D5100 weighs 560 g (1.23 lb / 19.75 oz)
and has external dimensions of 128 x 97 x 79 mm (5.04 x 3.82 x 3.11″)
. Considering that the average weight of DSLR type cameras is 773g, Nikon D5100 is a remarkably light camera for its class. With a thickness of 79mm, it has an average thickness for its class.
Here is the front and top view image of Nikon D5100 with the dimensions:
In order to give you a better idea about the real life size of Nikon D5100, we have added an image of how it looks next to a credit card and an AA type battery.
Now let's compare Nikon D5100 size with the camera that it replaced: Nikon D5000. Nikon D5100 is 7mm shorter and 1mm thinner than Nikon D5000 but it is also 1mm wider.
Below you can find the comparison of the weight and thickness of Nikon D5100 with its main competitors:
Nikon D5100 doesn't have any environmental sealings on its body so you got to be extra careful to protect it against water and dust. If you shoot under these conditions very often, consider checking Top DSLR Cameras with Weather Sealing page.