What is the largest unit of mass?

Answer 1

There is no largest unit.

-- In the SI (metric) system, there's only one unit of mass. It's called the kilogram,

and people who need to work with larger units just add other prefixes, like milli-,

micro-, nano-, mega, giga-, etc. to indicate larger or smaller multiples of grams,

in factors of 1,000.

-- In the Burmese, Liberian, and US Customary system, there are several different

units of mass. The biggest one I know of is the 'Slug'. That's the amount of mass

that accelerates at the rate of 1 foot/second2 when you push on it with a force of

one pound-force. You can always spot a Slug on Earth, because it weighs 32.2 pounds.