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 Olympus E-M10 IV and Nikon L840 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). Nikon L840 has external dimensions of 114 x 89 x 96 mm (4.49 x 3.5 x 3.78″) and weighs 538 g (1.19 lb / 18.98 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-M10 IV and the Nikon L840. Olympus E-M10 IV is 5mm shorter and 47mm thinner than Nikon L840 but it is also 8mm wider. As you can tell, actually this is not a fair size comparison since Nikon L840 has a built-in lens but Olympus E-M10 IV doesn't. Once you put a lens on E-M10 IV, its thickness will increase significantly.
Here is the back view size comparison of the Olympus E-M10 IV and Nikon L840.
Now lets look at the top view comparison of Olympus E-M10 IV and Nikon L840.
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 (155g ) than the Nikon L840 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 E-M10 IV, the total kit will weigh much higher.
Unfortunately neither the Olympus OM-D E-M10 IV nor Nikon Coolpix L840 provides any type of weather sealing in their bodies, 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 Top Bridge Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-M10 IV and Nikon L840'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.