Depends; they get smaller with use as resharpening removes material each time. Some were made just from spalled flakes that got their edges tuned up & don't have a recognizable stem. Some so small they were held between finger & thumb, others were hafted to a shaft (some of those started as knives, & with use worn off in a rounded pattern). Eventually they get small enough to lose their utility as a tool & are discarded.
are they typically that small?
Just like our stuff-if you go into the hardware store, you will see fifty sizes of screwdrivers, chisels, planes, knives, and such. Which one you use depends on what you're doing with it.