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 L31 and Sony W320 side-by-side from the front, back and top in their relative dimensions. Nikon L31 has external dimensions of 96 x 59 x 29 mm (3.78 x 2.32 x 1.14″) and weighs 160 g (0.35 lb / 5.64 oz) (including batteries). Sony W320 has external dimensions of 93 x 52 x 17 mm (3.66 x 2.05 x 0.67″) and weighs 117 g (0.26 lb / 4.13 oz) (including batteries).
Below you can see the front view size comparison of Nikon L31 and Sony W320. Sony W320 is clearly the smaller of the two cameras. Its body is 3mm narrower, 7mm shorter and 12mm thinner than Nikon L31.
Here is the back view size comparison of Nikon L31 and Sony W320.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Sony W320 is significantly lighter (43g ) than the Nikon L31 which may become a big advantage especially on long walking trips.
Unfortunately neither Nikon Coolpix L31 nor Sony Cyber-shot DSC-W320 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 Compact Cameras with Weather Sealing
LCD Screen Size and Features
Nikon L31 and Sony W320's LCD screens has the same diagonal size of 2.7".
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.