A 6 foot tall person is roughly 1828mm tall. A 5’11” tall person is 1803mm tall. So you can use 1800mm as an easy start for a person’s height – with variance.
This would be 1 to 1 scale (1:1 or 1/1), also known as life-size or full-size.
Three quarter scale (3:4 or 3/4) is almost full-size. A 6 foot tall person would be 4’6” tall or about 1350mm.
Half scale (1:2 or 1/2) is the next one down and a common scale. A 6 foot tall person would be 3’ tall or about 900mm.
One quarter scale (1:4 or 1/ 4) is another common one. A 6 foot tall person would be 18” tall or about 450mm.
Doll scale is one sixth (1:6 or 1/6). A 6 foot tall person would be 12” tall or about 300mm (304mm). Barbies, the big GI Joes, and the large Star Wars figures were this scale.
Action figure scale is about one ninth (1:9 or 1/9). A 6 foot tall person would be about 8” tall or about 225mm. Mego figures, and larger superhero figures are this scale.
Dollhouse scale or 1 inch scale is one twelfth (1:12 or 1/12). A 6 foot tall person would be 6” tall or 150mm. The Star Wars Black Series figures are this scale. He-Man was close to this scale (about 5.5”).
A large model car scale is 1:18 or 1/18. A 6 foot tall person would be 4 inches tall or about 100mm.
Small action figures (Star Wars and GI Joes) are a bit smaller than this. These figures are 3 ¾” tall or about 95mm.
The next scale is very popular. It is a common model car scale, and the same scale as Playmobil figures. This is 1:24 or 1/24 scale. For doll houses, it is also known as half inch scale A 6 foot tall person would be 3” tall or 75mm.
Another popular scale for model cars is 1:32 or 1/32. A 6 foot tall person would be 56mm tall. This is known as 1 scale in trains and was roughly they scale for the Thomas the Train sets.
A popular scale for army figures is 1:35 or 1/35. A 6 foot tall person would be 2” tall or between 50mm and 52mm.
From experience, even though they should fit easily, it still takes a lot of work to fit a 1/35 figure into a 1/32 model car.
O scale trains are about 1:43. A 6 foot tall person would be about 42mm.
Lego minifigs are oddly shaped – wide for their height. They are 1:40 or 1/40. A 6 foot tall person would be 40mm tall. This is also the scale for Marvel Crisis Protocol.
Another fairly common model scale for army vehicles is 1:48 or 1/48. A 6 foot tall person would be 38mm tall. This is the scale for Dust Tactics and Dust 1947. Mega Size Model Gundams are in this scale.
A lot of newer miniature game figures are now coming out in what would be 1/56 scale. A 6 foot tall person would be 32mm tall.
Perfect Grade Gundams are in 1:60 scale. A 6 foot tall person would be about 30.5mm tall.
Heroic scale would be about 1/65. A 6 foot tall person would be 28mm tall.
Hot Wheels cars are actually 1/64 scale but, due to the bases and bulk of these figures, look too small for them.
The former popular scale for miniature games was 1/72. A 6 foot tall person would be 1” tall or 25mm. This is still very popular for army figures. Note that due to their bulk, most 25mm figures look huge compared to the 1/72 plastic models.
1/76 model airplanes will also be close in scale but look very small due to the bulk of these figures. A 6 foot tall person would be 24mm.
HO scale trains are 1/85. A 6 foot tall person would be 22mm tall.
There were also some smaller miniature figures in what would be 1/90 scale. A 6 foot tall person would be 20mm tall, however figure at this scale were often measured to the eyes instead of the top of the head (due to helmets) so 20mm figures are probably closer to HO scale.
Master grade, and some High Grade Gundams are 1:100 scale. A 6 foot tall person would be 18mm tall.
In the UK a very popular size for miniature wargames would be about 1/120. A 6 foot tall person in this scale would be 15mm tall.
Another scale for airplane models is 1/144. A 6 foot tall person would be 12.5mm. Gundams in Real Grade, Entry Grade and most High Grades are in this scale. Wings of Glory/Wings of War airplanes were suppose to be 1/144 scale but a figure this size would never fit. They are probably closer to 1/200 scale.
N scale trains are between 1:148 to 1:160. A 6 foot tall person would be 12mm to 11.5mm.
Micro Machines were close to N Scale – between 1:148 and 1:160 for most vehicles, and figures about 1/77 scale. They weren’t always consistent though and included larger scale vehicles as well even smaller for spacecraft.
Another common scale for bigger battles is micro armor scale (1:285 or 1/285). A 6 foot tall person would be 6mm tall. Battletech is also supposed to be in this scale.
Naval scale wargames run the range from 1:1800 for the Axis and Allies:War at Sea game, through 1:2400, 1:3000, 1:4800, up to 1:6000.
Star Fleet Battles had ships in 1/3788 scale.