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 D3400 and Canon G7 X MII side-by-side from the front, back and top in their relative dimensions. Nikon D3400 has external dimensions of 124 x 98 x 76 mm (4.88 x 3.86 x 2.99″) and weighs 395 g (0.87 lb / 13.93 oz) (including batteries). Canon G7 X MII has external dimensions of 106 x 61 x 42 mm (4.17 x 2.4 x 1.65″) and weighs 319 g (0.70 lb / 11.25 oz) (including batteries).
Below you can see the front view size comparison of Nikon D3400 and Canon G7 X MII. Canon G7 X MII is clearly the smaller of the two cameras. Its body is 18mm narrower, 37mm shorter and 34mm thinner than Nikon D3400. As you can tell, actually this is not a fair size comparison since Canon G7 X MII has a built-in lens but Nikon D3400 doesn't. Once you put a lens on D3400, its thickness will increase significantly.
Here is the back view size comparison of Nikon D3400 and Canon G7 X MII.
Now lets look at the top view comparison of Nikon D3400 and Canon G7 X MII.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon G7 X MII is significantly lighter (76g ) than the Nikon D3400 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 D3400, the total kit will weigh much higher.
Unfortunately neither Nikon D3400 nor Canon PowerShot G7 X Mark II 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 Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Nikon D3400 and Canon G7 X MII's LCD screens has the same diagonal size of 3.00".
On the other hand, Canon G7 X MII 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 Nikon D3400 has a fixed type screen which provides less flexibility in shooting positions compared to G7 X MII.