Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Leica Q-P and Fujifilm X-A3 side-by-side from the front, back and top in their relative dimensions. Leica Q-P has external dimensions of 130 x 80 x 93 mm (5.12 x 3.15 x 3.66″) and weighs 640 g (1.41 lb / 22.58 oz) (including batteries). Fujifilm X-A3 has external dimensions of 117 x 67 x 40 mm (4.61 x 2.64 x 1.57″) and weighs 339 g (0.75 lb / 11.96 oz) (including batteries).
Below you can see the front view size comparison of Leica Q-P and Fujifilm X-A3. Fujifilm X-A3 is clearly the smaller of the two cameras. Its body is 13mm narrower, 13mm shorter and 53mm thinner than Leica Q-P. As you can tell, actually this is not a fair size comparison since Leica Q-P has a built-in lens but Fujifilm X-A3 doesn't. Once you put a lens on X-A3, its thickness will increase significantly.
Here is the back view size comparison of Leica Q-P and Fujifilm X-A3.
Now lets look at the top view comparison of Leica Q-P and Fujifilm X-A3.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Fujifilm X-A3 is significantly lighter (301g ) than the Leica Q-P which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on X-A3, the total kit will weigh much higher.
Unfortunately neither Leica Q-P nor Fujifilm X-A3 provides any type of weather sealing in their body, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Compact Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Leica Q-P and Fujifilm X-A3's LCD screens has the same diagonal size of 3".
On the other hand, Fujifilm X-A3 features a Tilting screen
where you can change the angle of the screen to make it easier to shoot from waist or over the head levels whereas the Leica Q-P has a fixed type screen which provides less flexibility in shooting positions compared to X-A3.