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 A100 and Sony W810 side-by-side from the front, back and top in their relative dimensions. Nikon A100 has external dimensions of 95 x 59 x 20 mm (3.74 x 2.32 x 0.79″) and weighs 119 g (0.26 lb / 4.20 oz) (including batteries). Sony W810 has external dimensions of 97 x 56 x 21 mm (3.82 x 2.2 x 0.83″) and weighs 111 g (0.24 lb / 3.92 oz) (including batteries).
Below you can see the front view size comparison of Nikon A100 and Sony W810. Nikon A100 is 2mm narrower and 1mm thinner than Sony W810 but it is also 3mm taller.
Here is the back view size comparison of Nikon A100 and Sony W810.
Now lets look at the top view comparison of Nikon A100 and Sony W810.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Sony W810 is 8g lighter than the Nikon A100 but we don't think this will make a significant difference.
Unfortunately neither Nikon Coolpix A100 nor Sony Cyber-shot DSC-W810 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 A100 and Sony W810'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.