First things first, before doing any calculations, we need to figure out what the mass of these ponies are.

We're going to start off by finding the height of one of the ponies.

(Most of these short clips will have downloadable links beneath them.)

(In the original image the heights were actually 840 pixels and 255 pixels. The picture was shrunk so it would take up less space on this page.)

Luckily for us, all of the mane 6 have bodies with very similar dimensions. (There are additional appendages like wings and horns.)

Thus, we can use a 1:1 ratio between all of the mane 6 ponies. 

This is a really busy picture, so here's everything as shown above:

Mane 6 height: 265 pixels

Mane 6 height to withers: 144 pixels

Mane 6 height of torso: 64 pixels

Mane 6 length of torso: 111 pixels

Celestia height: 431 pixels

Celestia height to withers: 273 pixels

Celestia height of torso: 72 pixels

Celestia length of torso: 182 pixels

The reason that this image has measurements for the height from the ground to the base of there neck (withers) is because this is the method used for measuring the height of ponies and horses in real life, and this length is measured in hands, which is 4 inches. 13.2 would be 13 hands and an additional 2 inches, or 54 inches.

See this link for more information (as well as a table for approximating mass of regular horses): http://horsetalk.co.nz/2013/01/18/working-out-horse-weight/#axzz2n8gd6M6j

This website also provides a way to estimate the mass of a horse based on its dimensions.

Mass in kg = (Girth)^2 * Length / 11000

Where girth and length are measured in centimeters.

8 feet = 243.84cm

Mane 6 Height: 243.84cm * (255/840) * (372/249) = 110.588cm

Mane 6 Girth: 110.588 * (64/265) * pi = 83.906cm

Mane 6 Length: 110.588 * (111/265) = 46.322cm

Mane 6 Mass ~ (girth)^2 * length / 11000 = 29.647 kg

Celestia's Girth: 110.588 * (72/265) * pi = 94.394cm

Celestia's Length: 110.588 * (182/265) = 75.951cm

Celestia's Mass ~ (girth)^2 * length / 11000 = 61.523 kg

It would appear that the ponies here are much less massive than real world ponies.

---

---

On February 1st, Pinkie Pride was released, which includes the following two images in it.

Using these values, we get

6 feet = 182.88 cm

182.88 cm * (507/672) * (455/567) = 110.721825 cm

The height calculated for the mane 6 from the candy cane is 110.588cm.

Yay continuity :)