I have seen in episodes over the years Bob Vila comment how a rooms dimensions are ideal or classical. I believe one time he mentioned a width to length ration of 1 to 1.5 so a 10 foot wide room should be 15 feet in length. While this formula if I remembered it correctly would work in some rooms what I would like to understand the architecture theory behind room dimensions of length and width to ceiling height.

I am sure all can agree that the ratio of these dimensions contribute greatly to feeling someone has when entering and being in a room.

I have searched and searched the internet and cannot seam to find any guide that gives suggested dimension ratios for various rooms types and the feeling your trying to create (formal, casual, cozy, grand, intimate, etc etc).

Bob, if you are reading this, I think this is something that would be of great help to people when they are designing their homes.

Thanks for your help.

I'm also interested in this topic. I am planning a modern home soon and would like to try to one of the software programs on the market. Asw I was thinking about using the program the same question came to mind. What are the rules of thumb for room size?

I've had the same question in the past and couldn't find any info on it, so I measured a variety of rooms in homes, at work, etc. and have come to several conclusions. One is that when the length and width vary by more than the 1.5 ratio you mentioned, there seems to be the perception that the space is not so much a "destination, or "room," but more a "passageway" to somewhere else, like a hallway.
The second thing I've noticed about room dimensions, if that the height component is as important as length and width when it comes to the perception of size. Increasing the ceiling height from 8 to 9 feet has a more dramatic effect on my senses than increasing the length or width by a foot.

Personally, I prefer the visual interest of odd wall angles and bump-outs to a purely rectangular room, if the space and budget allows. It really pays to look at some of the newer homes on the market to get ideas on how to create the feeling you're looking for. I’ve been finding that getting away from the rectangular shape makes it more difficult to quantify size, and allows smaller rooms to look larger than they really are.

The ratios mentioned in your question are somewhat based on 'sacred geometry' and what is called the golden mean. It is actually 1.618 and is the ratio for example of how the nautilus shell expands. I have done a little reading on this and designed the built-in bookshelf for our TV room based on this. There are also height and volume calculations that can be incorporated that will affect how the room feels.

yes, the golden ratio 5/8 is the right one for visual comfort.

Another is maximum size.
The Victorians noted that humans will not generally use a space larger than 14'x14'. Make a large grand entrry or ballroom or great room and people will tend to congregate on spaces of 14x14 or smaller. Build a room that is 13 x 21 and you have the right proportions, but the furniture arrangement will likely be in one portion of the room, not using all of it.

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