Beginner's Guide to Interior Design - Chapter 4: Principles of Design



The principles of design are the set of tools that are gathering and shaping the existence, type and intensity of the elements to achieve harmony in the design of your room. While Elements of design can change or not exist according to the design style and purpose, principles of design will exist in any interior design. Principles of design are the basic "Rules" you should follow in every design of space, with the main purpose of  making a correct and balanced use in the elements of design, in a way that will fit to the design style, purpose and functionality of the room.








Refer to the relationship of objects or parts of objects to one another and to the design as a whole. In a more simple manner, how the relationship between pieces of furniture, decor and walls integrate with the overall appearance of the room design. Furniture should always be in visual proportion to other pieces of furniture in the room and the wall in which it will be placed.


Scale refers to the Absolute size of objects compared to the space. Meaning the actual size for objects compared to the actual space of the room. The key to the correct use of scale is placing objects that are appropriate to the size of the room, as well as to the human dimensions.


Proportion refers to the Relative size and ratio of objects compared to other objects and to the space. Meaning, the size of an object, compared to to other objects, and to the size of the space.Furniture and Decor may be in Proportion to themselves, but they must also be in Scale  to the space of the room.


Grand  Scale room, features, and furniture. Large furniture and features are in  Proportion to the large Scale room.

Small mall Scale room, features, and furniture. Small furniture and features are in Proportion to the small scale room. Scale room, features, and furniture. Small Furniture and features are in Proportion to the small Scale room. 


1. Too Big, Too Small, Just Right -  In the following example we can see how changing one object - the chair - influence the entire scale and proportion of the design. 

Too Big - The chair large scale diminishes everything around it.

Too Small - The chairs light palate accentuates its skinny, small scale.

Just Right  - This chair matches the scale and proportion to other objects in the room.

2. Too Much, Too Little, Just Right -  In the following example we can see how quantity and space between objects  influence the scale and proportion of the design. 

Too Much -There’s no time to pause to consider any single object, since they are all stepping on one another’s toes in a jostle for space.

Too Little - Too much space between objects makes the candlesticks and the too-small frame look lonely, the bare wall yawning above.

Just Right - The weight now shifted to the left side, fewer items are needed there for balance..


Ratio in interior design is defined as the relationship between size dimensions of an object or between objects. For example, a square table with the size of  20 " wide X 20" inches long, will have a ratio of 1:1, since the dimensions of the table width is exactly as the dimensions of the table length. However if we have a table with the dimensions of 20" wide X 40" long, then the ratio would be 1:2.

Rectangular ratios and uneven ratios are generally giving the best effect for interior design. They are more pleasing to the eye. Ratios like 2:3, 3:5 or 5:8,

The Golden Ratio (2:3)

The golden ratio of 2:3, is considered to be the most proportionality and pleasing ratio in design.This ratio has a wide usage in interior design and architecture and is considered the most comfortable to the eye.  Using the golden ratio in the design of your space in objects and between objects is the best option and will create a sense of balance and harmony in the design of the room.

24"x36" (Ratio 2:3) Oil painting "Golden Squares"

Paris Eiffel Tower, keeping a 2:3 ratio between the tower sections.

2:3 Ratio between the lower wall to fireplace, and between the lower wall part to higher wall part.


1. Scale & Proportion in Interior Design - (Source: The Spurce)

2. Scale and Proportion - (Source: VRA Interiors)

3. How to use Scale and Proportion in your Space - (Source: Heather Scott Home Design)


Balance is defined as the use of elements in the goal of creating an equal visual weight in the design of your room. Each piece of furniture or decor has it’s own visual weight, which can be given according to it’s size, color, pattern or form. The idea of balance is to use the elements of design in a sense that will create harmony and equilibrium. It's important the room will be in balance in order to feel comfortable in it.


Symmetrical balance is the arranging of objects on one side of an imaginary central line and creating a mirror image of this arrangement in the opposite side. This type of balance is more formal and give a sense of stability. I'ts also very easy to arrange the objects in the room in Symmetrical Balance. However, in some designs using Symmetrical Balance can be perceived as static and dull.



Asymmetrical balance is when elements on either side of an imaginary central line are unmatched but appear to be in balance. Different sizes, forms, textures and colors may be used to achieve this look. The idea of Asymmetrical Balance is to use each element in the right quantity, intensity and spread across the space. Asymmetrical Balance can be more interesting to the eye however harder to achieve successfully. 

(Source: MM Interior Design)

The design above is a good example for the correct distribution of elements in Asymmetrical Balance. The sofa is equally balanced to the 2 chairs on the other side. The pillow patterns and color is spread in the correct space and quantity. The gold decor accents such as the lamp and vase are distributed in the right dosage. 

(Source: Robin's Nest Interiors)

Colors Balance: The design above is a good example for a balanced distribution of colors. Although bold colors like orange and pink are used in the design, they are balanced correctly among the different objects, thus creating harmony in this playful modern room design.


Rhythm is defined as the movement between different elements of interior design. Rhythm creates an effect of moving the visual weight in the room by using certain colors, lines, forms, or textures in a regular pattern. Rhythm is used to move the eye in a specific pace and a specific path, using the elements that illustrate it. It's also used and to direct the eye to a specific point in the room, usually the Focal Point. There are 4 main types of Rhythm.


Radiation occurs when lines radiate from a central point; chairs around a round table, small items grouped around a large one.

(Source: Tara Fee Interior Design)


repeating shapes,colors forms in unified manner. to help your eye move throughout the room. Repetition can be found in the repeating stripes on wallpaper, design in a tile floor, or woodwork that runs at the top or bottom of a wall or in the pattern of an area rug.


NuLOOM Hand Knotted Luxurious Viscose Chevron Kelli Rug Black


Gradation is the gradual increasing or decreasing of color, size, or pattern.

(Source: Pinterest )

(Source: Pinterest)


As given by it’s name, emphasis is about creating a central point - like a different colored wall, an artwork, or a unique furniture - and arrange the design to point out at the central point of the room, also called the Focal Point. Focal point is given due to the idea that an equal importance of objects in a design could either seems boring or scattered.


1.Choose an Object or feature should be worthy of being singled out for attention. In many cases an artwork is the object used for Focal point. 

2 . The Focal point object should be the most dominant object in the room, but not overpower the rest of the room design.

3. No other object or feature should compete for attention with the Focal Point Object

(Source: Decoist)


"The White Tree" Metal Wall Art


"Lady at Bay" Metal Wall Art


Depend on the room design style and purpose, we can either use a mix of both form types or use only one form type.  How to work with forms will be more clear as we progress with the chapters of the guide, the general idea though is to balance between the form types to get the desired outcome.


Unity and variety are 2 principles that are combined together to create an harmonious effect, both in furnishings and in architecture.


Unity occurs when all the parts of a design are related by one idea; this creates harmony. Can create unity by repeating like items in a design, but it's not sameness.


Variety occurs when different styles and materials are combined. Adds interest to a design, but too much creates confusion

The key in using this principle is to create a balanced combination between Unity and Variety. Too much Unity can create a dull boring appearance. Too much variety can create confusion and over stimulation.  A correct balance between Unity and Variety will create an interesting appearance on one hand and harmony of the design on the other. Here are a few examples that illustrate this principle.

This design shows a good combination between Unity and Variety. The color scheme of blue and cream colors creates an harmony in the appearance of the room. The mix of different patterns - The pattern of the pillows and table, the pattern of windows and pattern of chair - creates a more interesting and alive feeling to the design.

(Source: Heather Scott Home & Design)

Similar example can be found in this design. Unity is done in this design is given by unified Color Scheme that combines Yellow, Black and White. Moreover, Unity is given by the use of leather texture in all chairs ottomans, and sofas. Variety is given by the different patterns used in pillows, and rug, as well as in the frames above the sofa.

(Source: Tara Fee Interior Design)


Making a use of the principles of design in any space, room or style you chose will ensure that the design of the room will have balance and harmony. So no matter what design style you chose to go for, what is the purpose of the room and is the intensity of existence of each element. The principles of design should apply in any design of space. 

This guide was written by Amit Roznak and Mathew'z team