Phi and the Golden Section in Architecture

Phi (Φ)the Golden Section, has been used by mankind for centuries in architecture.

Its use started as perhaps early as with the Egyptians in the design of the pyramids.  When the basic phi relationships are used to create a right triangle, it forms the dimensions of the great pyramids of Egypt, with the geometry shown below creating an angle of 51.83 degrees, the cosine of which is phi, or 0.618.   (See more on this at Phi, Pi and the Great Pyramid of Giza.)

The Parthenon

The ancient Greek Euclid ((365–300 BC) wrote of it in “Elements” as the “dividing a line in the extreme and mean ratio.”   The Parthenon, built in 447 to 438 BC, appears to use it in some aspects of its design to achieve beauty and balance its design.  The illustration below shows one of the ways that the golden ratio is often reported to appear in its design. This, however, is subject to some debate, as the application of the golden ratio is often not accurately described in many sources. Furthermore, using the second step of the Parthenon seems somewhat arbitrary. There are, however, other dimensions of the Parthenon which appear to be golden ratios. This is discussed in more detail at The Parthenon and the Golden Ratio.

Phi, the Golden Ratio, design proportions in an architectural rendering of the Parthenon in Athens

Notre Dame

Notre Dame in Paris, which was built in between 1163 and 1250 appears to have golden ratio proportions in a number of its key proportions of design.  Although it is rather asymmetrical in its design and difficult to measure photographically because of parallax distortions, the golden ratio lines of the green, blue and red rectangles conform closely to the major architectural lines, which represent:

  • Red – Vertical height of base at ground level : Top of first level : Top of second floor
  • Blue – Vertical height of base of second level : Top of second level : Top of third level
  • Green – Horizontal width of outside of left top section : Inside of top right section : Outside of top right section:

Notre Dame in Paris illustrating golden ratios

The Taj Mahal

Renaissance artists of the 1500’s in the time of Leonardo Da Vinci knew it as the Divine Proportion.  In India, it was used in the construction of the Taj Mahal, which was completed in 1648.  Click on photos below for enlarged image.


The United Nations Secretariat Building

The United Nations building also reflects the golden ratio in a number of aspects of its design, as described in more detail on the UN Secretariat Building page.

Toronto’s CN Tower

The CN Tower in Toronto, the tallest tower and freestanding structure in the world, has contains the golden ratio in its design. The ratio of observation deck at 342 meters to the total height of 553.33 is 0.618 or phi, the reciprocal of Phi!

Thanks go to Moein Danesh for the contribution of information on the Taj Mahal and to John Owen for his contribution of this information on the CN Tower


  1. says

    It’s incredible! We are searching for sophisticated solutions, and invite new ways to build higher, and more magnificent buildings, where even our predictors knew simplest and most practical rules even used today… I think we should go back to our roots. Regards. Dom

    • Wal says

      I urge you to watch The Revelations of the Pyramids (YouTube) – a fantastic insight into the amazing pyramids in Egypt, Peru, Mexico and China (YES China !!??) It’s about 100 mins long but such compelling viewing it goes very quickly. The Pi and Phi usage and the generall feat of the constructions is mind blowing! I hope you enjoy! Regards, Wal

  2. Steven says

    When carpenters are building stairs there is a general rule that they follow in order to build a comfortable set of stairs. If you add the rise of the stair to the length of the run ( in inches ) you should get close to eighteen. A very nice rise ( especially for older folks ) is 6 3/4″ . Combine that with an 11″ run and you have a very comfortable set of stairs. 11 divided by 6 3/4 is 1.629… VERY close to PHI! This makes sense since the human body has the phi ratio all over it.

      • says

        That’s true, but from a practical viewpoint an 18″ run would result in a run of 11.1246118…” and a step height of 6.875388203…”, and no carpenter is going to be that precise. Note how the following more realistic options produce a result that illustrates a phi relationship:

        Step Run Ratio
        7.000 11.000 1.571
        6.875 11.125 1.618
        6.750 11.250 1.667

    • says

      Either is correct, depending on the application as they are reciprocals of one another. If the ratio of the larger to the smaller is 1.618, then the ratio of the smaller to the larger is 0.618. 1.618 is often denoted as Phi with a capital “P” while 0.618 is denoted as phi with a lower case “p.”

  3. Proumchin Vicheth says

    I am an architect student in year 2. I am curious about the golden ratio. what is exact meaning of it? Could you give me more example or explain more about it?

    • Jon Donnis says

      I’m not buying into the “fact” that everything in nature is fractally composed of fractals.

      Nor do I see the relevance of a few buildings which many will claim have no relationship to Phi.

      I call pseudoscience, sorry Gary.

      • says

        Some may claim that the buildings have no relationship to phi, but then where are their measures and evidence? You can’t just “refute” and “call pseudoscience” without presenting evidence to the contrary and then call it “science.” The images presented here and on the other pages referenced on the site give examples of golden ratio proportions. No statement is made that everything in nature is in golden ratio proportions either, but rather that it appears so commonly as to not be chance. Also, no “science” is implied in the application of phi to architecture. It’s just an artistic design choice to use proportions commonly found in nature and basic geometry, and that for those reasons appear natural and pleasing.

  4. Jacob Hall says

    Does the Golden Ratio have any value for creating structures with durability? Sure, it looks pretty, but does it make things last when compared to other ratios?

    • says

      Dear Jacob,
      I would like to say yes, from my understanding of ‘Sacred Geometry’..there is always something so special with the ratios of let us say the ‘Divine Proportion’ The smallest point is indicative of the Highest point. And therefore one asks …what is the microcosmic/macrocosmic relationship. One particular answer is as it were the Alpha and the Omega. We are dealing a sbject on an eternal level…if that is purely a conceptional view point or simply philosophical, I would suggest that it so important to bring into one’s equation of understanding that we can be dealing something so very real…that it is the unknown reality it’self and that the cosmos and life on earth is so valuable. It makes me wonder how it is possible to be as synic..not saying that you are …just saying that there is a great wonder to be deeply respcted universaly but in todays times on earth even so most importantly.We need to value nature on a level such as is so importantly required today and also that is it were not just human life but that of all creation and more fracking..God bless take care.. I hope we will all come more sensitivity to this very wonderful ‘world’ – enviroment that we do need to take care of–many blessings..all the best William

  5. Vibhushit says

    Hello… I’m an student of architecture. thank you for sharing this information. I’m very inspired with Golden Ratio and I want to use it in my design problem as a concept. Do you have some more information regarding this. How to use Golden ratio in buildings.?

    • says

      Just different names for the same thing. The Greek letter Phi represents the number 1.618…, just like Pi represents the number 3.14… This number is also known as the Golden Ratio/Mean/Section/Proportion or the Divine Proportion.


  1. […] Taj Mahal (Source) Parthenon (Source) Notre Dame […]

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