Now this is definately a good question to answer, not only is it the one thing that can finally settle the King of Monsters growth problems, but it is also a way for people to start really thinking. These are simply my own opinions/guesses/estimations/so on, so do not start being cridicts. Thanks, and as always, Enjoy.
Toho: Every stage was built in a slightly inconsistant scale, the majority being 1/25 and 1/50, this is probably the most important part of solving Godzilla's true height, it might even be the only part we need. So, Godzilla stared in his first film during 1954, and at this point he was 50 meters tall (164 to 172 Feet). Well, let's see, we need to compare godzilla to the things he destroys, multiply their scale size to the max of the two most popular scales used (1/25 and 1/50). Then, and only then, can we determine Godzillas true mass.
First, Utility Poles, these things reach a standard height of 12 meters with just a few exceptions. Some can be about 37 meters tall, which is, after doing a bit of calculation, around 48% of godzilla's height in the first film, or 0.somewhere withing 0.9 and 0.8 meters Godzilla's suit is 2 meters tall). However, when you get to the scene of Godzilla actually destroying such a structure, you can clearly see it's higher than that. The top of that Utility Pole was around the Mid-Base of the suit's neck. Making this Utility Pole too high, and, as a result, forcing us to downgrade our Monster.
Utility Pole 37m. summit = 1/5 of the neck/head (which collectively is 0.5 meters making that 0.1 meters)
1.5 meters of the general suit (Where the actor is) + 0.1 meters from 1/5 of the Neck/Head = (Below)
1.6/2.0 meters AKA exactly 80% of Godizilla's height
Now if that's correct we shall find out how big this makes godzilla 1954 in the end. and the new answer is.
Exact height of Godzilla 1954 =44.2 meters tall