Canon 450D weighs 524 g (1.16 lb / 18.48 oz) and has external dimensions of 129 x 98 x 62 mm (5.08 x 3.86 x 2.44″). Considering that the average weight of DSLR type cameras is 773g, Canon 450D is a remarkably light camera for its class. Even better, with a thickness of only 62mm, it is also quite small, 14mm thinner than the average of its class.
Here is the front and top view image of Canon 450D with the dimensions:
In order to give you a better idea about the real life size of Canon 450D, we have added an image of how it looks next to a credit card and an AA type battery.
Now let's compare Canon 450D size with the camera that it replaced: Canon 400D. Canon 400D is 2mm narrower and 4mm shorter than Canon 450D but it is also 3mm thicker.
Below you can find the comparison of the weight and thickness of Canon 450D with its main competitors:
Canon 450D 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.