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 Olympus E-M10 IV and Leica M10 side-by-side from the front, back and top in their relative dimensions. Olympus E-M10 IV has external dimensions of 122 x 84 x 49 mm (4.8 x 3.31 x 1.93″) and weighs 383 g (0.84 lb / 13.51 oz) (including batteries). Leica M10 has external dimensions of 139 x 39 x 80 mm (5.47 x 1.54 x 3.15″) and weighs 660 g (1.46 lb / 23.28 oz) (including batteries).
Below you can see the front view size comparison of Olympus E-M10 IV and Leica M10. Leica M10 is 4mm shorter and 10mm thinner than Olympus E-M10 IV but it is also 17mm wider.
Here is the back view size comparison of Olympus E-M10 IV and Leica M10.
Now lets look at the top view comparison of Olympus E-M10 IV and Leica M10.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Olympus E-M10 IV is significantly lighter (277g ) than the Leica M10 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 Leica M10 has a Full frame sensor and Olympus E-M10 IV has a smaller Four Thirds sensor, Olympus E-M10 IV's lenses for a similar focal length and aperture will generally be lighter and smaller than the Leica M10 lenses.
Unfortunately neither Olympus OM-D E-M10 IV nor Leica M10 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 Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-M10 IV and Leica M10's LCD screens has the same diagonal size of 3".
On the other hand, Olympus E-M10 IV 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 M10 has a fixed type screen which provides less flexibility in shooting positions compared to E-M10 IV.