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 Nikon D3500 and Nikon D5600 side-by-side from the front, back and top in their relative dimensions. Nikon D3500 has external dimensions of 124 x 97 x 70 mm (4.88 x 3.82 x 2.76″) and weighs 365 g (0.80 lb / 12.87 oz) (including batteries). Nikon D5600 has external dimensions of 124 x 97 x 70 mm (4.88 x 3.82 x 2.76″) and weighs 465 g (1.03 lb / 16.40 oz) (including batteries).
Below you can see the front view size comparison of Nikon D3500 and Nikon D5600. In this case, we can see that Nikon D3500 and Nikon D5600 have the exact same height, width and thickness.
Here is the back view size comparison of Nikon D3500 and Nikon D5600.
Now lets look at the top view comparison of Nikon D3500 and Nikon D5600.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Nikon D3500 is significantly lighter (100g ) than the Nikon D5600 which may become a big advantage especially on long walking trips.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since both Nikon D3500 and Nikon D5600 have the same Nikon F lens mount and APS-C sized sensors, lenses will not be a differentiator on total size of the system.
Unfortunately neither Nikon D3500 nor Nikon D5600 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 DSLR Cameras with Weather Sealing
LCD Screen Size and Features
Nikon D5600's 3.2" LCD screen is slightly larger than Nikon D3500's 3" screen.
Moreover, Nikon D5600 sports a Fully Articulated screen
which you can change the angle and position of the screen almost freely, making it possible to shoot from waist or over the head levels, and especially very useful for shooting selfies and video. On the other hand, Nikon D3500 has a fixed type screen which provides almost no flexibility in shooting positions compared to D5600.