So since the last time I did one of these, someone proposed that I use Santa's door in A Very Minty Christmas to calculate the G3 ponies' heights.

Before we begin, here's an article estimating the G4 pony heights:
https://scifi.stackexchange.com/questions/15664/what-is-the-relative-scale-of-the-my-little-pony-universe

And another:

https://www.fimfiction.net/blog/728167/the-height-of-ponies-confirmed

Both seem to put them in the 3'-4' range from hoof to top of head. The first article tries to use the more anatomically correct hoof to shoulder estimates, but I want to compare apples to apples here.

So to start with, I wanted a scene with a G3 pony right next to a full screenshot of Santa's door.

I found one at arround 33:00 that meets that criteria:

So first, we draw a line arround the middle (the door is at a slight angle) to calculate the estimated height of the door:

This puts the door at about 353px.

Now we do the same for minty:

This puts Minty, in this frame, at about 225px.

So to find Minty's height, we can solve the proportional equation:

353 DoorHeightInches
----- = ---------------------------
225 MintyHeightInches

353 * MintyHeightInches = 225 * DoorheightInches

MintyHeightInches = 225 * DoorheightInches / 353

So, next, let's use Professor Bing, to try to get some estimates for Santa's height:

Of 4' 3'' or 51''

Meaning:

MintyHeight = 225 * DoorheightInches / 353 = 225 * 51 / 353 = 32'' = 2' 8''

meanwhile https://answers.yahoo.com/question/index?qid=20071217173349AAV89Rj, from the same search, gives:

An accepted answer of 6' or 72''.

And some other answers: 5' 10'' or 70'', 6' 3'' or 75'', 5' 2'' or 62'', and 6' 7'' or 79''

So, assuming Santa uses a custom door that's no taller then he is:

MintyHeight = 225 * DoorheightInches / 353 = 225 * 62 / 353 = 40'' = 3' 4''

to

MintyHeight = 225 * DoorheightInches / 353 = 225 * 79 / 353 = 50'' = 4' 2''

But...

Being G3, and the American Santa, he may use a standard American door, which is:

or 80''

So that would make Minty:

MintyHeight = 225 * DoorheightInches / 353 = 225 * 80 / 353 = 51'' = 4' 3''

this gives us a range of 2' 8'' to 4' 3''.
If we disregard a 4'' santa with his own 4'' door, we get: 3' 4'' - 4' 3'', or G4 height - 1 ft over G4 height.

What do you think, do you see any issues with my math? Any information I messed up, or missed out on?

That probably could be

G1, G2 and G3 ponies are roughly the same height and can G1s can carry kids and small humanoids. I'd say they are about the size of a class a welsh pony, 12-13 hands. Which puts them at 4 feet.

G3.5s and G4s are more likely the size of a Fallabella. Which is about 28-32 inches.