The Nano, on the other hand, comes in the smallest form factor Arduino offers, with the same 18 mm width but a shorter ... concerned with the board dimensions and weight, the safest bet is to ...

The Arduino Nano itself is the most basic and oldest ... It comes in a light seven-gram weight, with dimensions of 45 mm (length) by 18 mm (width). The Uno, on the other hand, is much bigger.