Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Sony RX10 IV and Sony A7 III side-by-side from the front, back and top in their relative dimensions. Sony RX10 IV has external dimensions of 133 x 94 x 145 mm (5.24 x 3.7 x 5.71″) and weighs 1095 g (2.41 lb / 38.62 oz) (including batteries). Sony A7 III has external dimensions of 127 x 96 x 74 mm (5 x 3.78 x 2.91″) and weighs 650 g (1.43 lb / 22.93 oz) (including batteries).
Below you can see the front-view size comparison of the Sony RX10 IV and the Sony A7 III. Sony A7 III is 6mm narrower and 71mm thinner than Sony RX10 IV but it is also 2mm taller. As you can tell, actually this is not a fair size comparison since Sony RX10 IV has a built-in lens but Sony A7 III doesn't. Once you put a lens on A7 III, its thickness will increase significantly.
Here is the back view size comparison of the Sony RX10 IV and Sony A7 III.
Now lets look at the top view comparison of Sony RX10 IV and Sony A7 III.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Sony A7 III is significantly lighter (445g ) than the Sony RX10 IV 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 A7 III, the total kit will weigh much higher.
Weather Sealing
Both the RX10 IV and the A7 III have weather sealings in their bodies, making them resistant to water and dust.
LCD Screen Size and Features
Sony RX10 IV and Sony A7 III's LCD screens have the same diagonal size of 3.00 inches.
Both cameras feature
Tilting screens where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels.