What is the average size of a viurs?

Answer 1

A medium-sized virion next to a flea is roughly equivalent to a human next to a mountain twice the size of Mount Everest. Some filoviruses have a total length of up to 1400 nm, however their capsid diameters are only about 80 nm. Most viruses which have been studied have a capsid diameter between 10 and 300 nanometres. Most viruses are unable to be seen with a light microscope but some are as large or larger than the smallest bacteria and can be seen under high optical magnification. More commonly, both scanning and transmission electron microscopes are used to visualize virus particles. Taken from Wikipedia, more info here: http://en.wikipedia.org/wiki/Virus#Size

Answer 2

The average size of a virus is typically between 20-300 nanometers in diameter. However, some viruses can be as small as 20 nanometers, while others can be larger, depending on the type of virus.