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The Rule of Three in Interior Design and How to Use It

The Rule of Three in Interior Design and How to Use It

The rule of three is an interior design technique that uses groupings of three items to create a focal point while balancing a space or a feature in the room.  This includes the furniture in seating areas, decor items on a shelf or table, and even the colors in the space by applying the 60, 30, 10 rule.  

The rule works by following symmetry and asymmetry.  If you want something to feel balanced, you make it symmetrical so it feels complete and you take everything in as a whole, this normally means even numbers.  If you want to have movement and bring eyes in, you use an odd number or take something off balance.  It could be as simple as having two similar items at equal lengths on a coffee table, or one dominant object on one side and nothing at the other.

Asymmetry brings your eyes in because everything is off balance, and that is where the rule of three comes in.  Three similar items, whether they’re the same or not, can balance the decor.  This uses the Gestalt Principles of Interior Design.  And by moving it so the tray aligns with the center of the coffee table, everything becomes balanced.  

symmetry vs assymetry using the rule of threes

There are a few ways to use the rule of three including:

  • Items grouped in threes
  • 3 sets of items
  • 3 colors in a space
  • 3 evenly spaced items

This is different from the rule of thirds in photography and art as the rule of thirds is about composition where you line up the focal points on a grid, one of three vertical or horizontal lines, or one of four intersecting points.  The rule of threes in interior design is similar because it can be used to create a focal point or balanced feel, but it is about grouping three objects or colors into the same space vs. composing art.

If you only had one item like a candle, the space would feel empty, two evenly spaced it feels balanced and everything blends in, but three items creates a nice focal point that brings attention to the space and makes it feel comfortable.  The only constraint is to make sure the three items grouped together are not too bulky or identical in size, texture, colors, or shape as this makes the space feel too crowded.  Something needs to build contrast for it to balance out.

rule of threes coffee table decor

It can be applied to most of the spaces in your home including decor items, lighting, and the layout of the room.  Here’s an example of how two symmetric pendant lights look great above a kitchen island and balance it out so the scene blends together using symmetry. 

Below you’ll see where a third light and a closer grouping uses the rule of threes to create a slight asymmetry and make the counter a focal point while the room still feels comfortable and balanced.

rule of threes with lighting

Here’s a few ways to use this concept in your home, office, or space to help create the effect you’re going for.

Furniture

There are a few ways to apply the rule of thirds to furniture including the furniture in the room, the decor items on the furniture, and to anchor a room.  The first is to have three complementary pieces so they balance each other out.

You could have a sofa with a matching love seat and a chair, or you could try a couch with two matching accent chairs.  A couch on its own in a room becomes a focal point where people know where to sit.  When you pair a couch with a love seat or accent chair next to it at an angle, you keep the focal point and draw attention to the coffee table and space directly in front, but it isn’t as conversational.
A non-equal sized couch like smaller loveseat on the opposite side makes things feel off balance as the symmetry is broken from the unevenly sized pieces of furniture.  By having three pieces of furniture you have a setting where everyone can look at one another and create an atmosphere for talking and engaging.  This is true whether you position the two chairs around a round coffee table or on the two ends of a rectangular one so the ends of the furniture line up.  The three pieces balance the room better than two uneven pieces so the sitting area is fully grounded.  Decor items can also be done in groups of three. 
On the couch try using three sizes of throw pillows on each side, or three of the same color going across.  Next to the couch on the side table place a plant, a vase, and a small stack of three books in a pyramid shape.  You can even do a coffee table with two matching accent tables to balance the entire sitting area.  The added bonus is everyone having enough space to set drinks, snacks, and their phones down comfortably.

Decor on Shelves

The first way to use the rule of threes on a shelf is to pick a shelf you want to bring attention too.  On the other shelves you can create a balanced and symmetrical look with photos in matching frames facing each other, and a third similar photo frame in the middle.  Another option is to use rows of books across the shelves so they balance the other shelves out.  On the focal point shelf, group the element you want to stand out in a group of three and center it. 

The shelves with equally spaced and balanced decor items will all balance each other out, and the shelf with the grouping of three items will stand out because it is different.  It will remain balanced because the odd number will bring eyes in and balance it as long as the pieces match in theme, color, or texture.
The next way if you want a maximalist approach is to fill your shelves with all the things you love, but put them in matching groups of three.  Try three similar sculptures, a photo from the beach with a seashell, and something else ocean themed.  Match three clay vases or jugs at different sizes, and three glass art objects like a vase, a bowl, and a jar.
As long as the sets of three match and create an associated experience, they’ll carry their own weight.  Just make sure the other groupings of threes balance them out visually so you don’t wind up with a chaotic look.  If this does happen, try using a patterned approach with one object on the left and a grouping of three on the right, then the next shelf down one object on the right and a grouping of three on the left.  The single object and grouping should all have the same theme.  The size of the groupings balances one another out.
using the rule of threes on shelves in a room

Colors, Textures, and Materials in the Room

The last way to use the rule of threes is to use the 60, 30, 10 or 70, 20, 10 rule of interior design.  60 or 70 percent of the main items should be one color or texture, 30 or 20 percent the next, and 10 percent for the last.  We’ll go with 60, 30, 10 for this example and three core colors.  

The walls and the area rug or carpet can be one color, the couch, chairs, and even vases or lamps, and frames for artwork on the walls can be the next.  The coffee table and accent tables can be the 10 percent while a tray on the coffee table can be part of the 30.
As long as you keep the colors and hues at this ratio including pillows, blankets, and other items in the same family, the room will balance.  Three is a way to have enough contrast so it doesn’t get monotonous or boring, and so you can experiment.  It works for other rooms too.
In bedrooms try using blankets, nightstands, pillows, and wall colors.  Bathrooms can use bathmats, shower curtains, tiles, counter tops, and the cabinetry.  It works with textures too.  60% can be stone like marble or granite, 30% can be wood including plants and woven baskets, and 10% can be the towels where you use cotton and linen or patterns and prints of trees and vines.
the rule of threes using colors

The rule of threes is your best friend when you want a space that feels comfortable, but has energy and balance.  You can apply it to decor items, furniture, and the color palette.  Once you start thinking in the number three, designing your dream space becomes easy as 1, 2, 3.

The Expand Furniture Editorial Team

The Expand Furniture Editorial Team

The Expand Furniture editorial team is composed of furniture designers, interior decorators, artists and professionals that render 3-D room visualizations, as well as advertising professionals.