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 Panasonic SZ3 and Nikon 1 J3 side-by-side from the front, back and top in their relative dimensions. Panasonic SZ3 has external dimensions of 95 x 56 x 22 mm (3.74 x 2.2 x 0.87″) and weighs 126 g (0.28 lb / 4.44 oz) (including batteries). Nikon 1 J3 has external dimensions of 101 x 61 x 29 mm (3.98 x 2.4 x 1.14″) and weighs 201 g (0.44 lb / 7.09 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic SZ3 and the Nikon 1 J3. Panasonic SZ3 is clearly the smaller of the two cameras. Its body is 6mm narrower, 5mm shorter and 7mm thinner than Nikon 1 J3. As you can tell, actually this is not a fair size comparison since Panasonic SZ3 has a built-in lens but Nikon 1 J3 doesn't. Once you put a lens on 1 J3, its thickness will increase significantly.
Now lets look at the top view comparison of Panasonic SZ3 and Nikon 1 J3.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic SZ3 is significantly lighter (75g ) than the Nikon 1 J3 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 1 J3, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-SZ3 nor Nikon 1 J3 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 Compact Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Nikon 1 J3's 3.00" LCD screen is slightly larger than Panasonic SZ3's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.