I'm going to do what Zalot already did:

Here's me with a football. A football is 11" tip to tip, or 27.94 cm. Because I'm an idiot, I used customary units in the pictures, so I'll convert in the text below:

A blocklander is about 3.5 footballs high, so that would be 97.79 cm, or 3'3". This means that a stud would be 19.558 cm, basically giving a 1:5 meter to stud ratio.
But what about a British football?

A British football can have a diameter of 6" or 15.24 cm (it varies).

A blocklander can fit about 3.75 British footballs, giving it a height of 2'8.4" or 82.5 cm. A stud would be 16.5 cm, meaning that there would be a 1:6 meter to stud ratio.
Just for fun, let's finish with a North Korean basketball:

A basketball has a diameter of 10" or 25.4 cm.

A blocklander can fit about 4.25 basketballs, giving it a height of 3'6.5" or 107.95 cm. A stud would be 21.59 cm, giving a meter to stud ratio of 1:4.42.
TL;DR: You're never going to get an accurate answer by comparing the avatars to random objects.