Formula to Figure Out Scale :
Figure Scale Number x 6feet x 12inches = Size of figure in inches
1:4 Scale ( approx.18″)
This scale is one of the largest common scales for action figures and is technically reserved for dolls, if we're going by the doll/action figure definition, as they often have "real" hair or cloth clothing. Examples of this format can be found in Sideshow's Premium Format figures and the superhero dolls made by Tonner.
1:6 Scale ( approx.12″)
This scale was the scale that the very first action figure (G.I. Joe) was. One of the more popular companies today that make 1:6 scale action figures is Hot Toys. They usually have unreal articulation and look like real people. They are very expensive but you probably won’t be disappointed.
1:9 Scale ( approx.8″)
This scale is pretty much exclusive to the Mego toy company's World's Greatest Heroes line of 8" action figures that ruled the toy aisles in the late '70s and early '80s. Other toy companies were quick to follow, such as Ideal with their famous monsters and Evel Knievel lines. This size became so popular, in fact, that G.I. Joe himself shrunk down to this size (although a petroleum shortage needed to make plastic didn't help, either).
1:10 Scale ( approx.7″)
For today's collectors, the 1:10 scale seems to be the king of the hill. Several action figure lines are being produced in this format from Mattel's DC Universe to Marvel's Lengends line. Mattel has made an even bigger splash with their Masters of the Universe Classics line that re-imagines the old school fantasy figures in a newer 7" scale. This size tends to be more popular with adult collectors than with children looking for play value.
1:12 Scale ( approx.5″-6″)
If the figure was based on a movie made during the '90s (Last Action Hero, Congo, Jurassic Park, Super Mario Brothers) their action figures were this size. Throughout the 1990s, figures ranging between 5-6" took over the action figure world, pretty much killing the 3.75" figures and setting a new standard. Although not very popular today, figures in this scale will never be forgotten.
1:18 Scale ( approx.3.75″-4″)
1:18 scale is by far the most popular action figure scale. I have taken a poll in the ToyArk forums and 70%+ of the collectors there prefer 3.75″ figures than any other. You can get figures in this size with lines like G.I. Joe, Marvel Universe, Star Wars, etc.
1:48 Scale ( approx.2")
It should be noted that with the rise in popularity and collectability of figures such as Lego "minifigs" and other miniature, yet fully articulated, figures from other building sets such as Mega Bloks, the 2" tall figure is starting to hold its own and is beginning to command respect in the collectibles world. These figures may very well one day be the reigning scale standard in the not too distant future, so they get an honorable mention here.