By Sukriti Wahi Interiors 13.04.2025

Why the ‘Rule of Three’ Is an Interior Design Trick That Always Works

Discover the interior design hack that interior stylists swear by.

Three wishes. The power of three (Charmed fans, assemble). “Third time’s a charm”.

Suffice it to say, three has long been known throughout history as a ‘magic’ figure — even the ancient Greek philosopher Pythagoras deemed the digit a divine number.

And as it turns out, the special numero also has sway in the world of interior design, with the ‘Rule of Three’ widely considered a décor hack that never fails.

Intrigued? Read on for everything there is to know about the ‘Rule of Three’ and how you can make it work in your home.

What is the ‘Rule of Three’ in Interior Design?

The ‘Rule of Three’ is an interior design principle in which furniture and décor items are grouped in threes to make a space appear natural, visually appealing and cohesive. Pieces can be grouped by shape and size, texture and even color.

As for why it’s so effective? Interior design commentator and content creator Nick Lewis explained that the rule works well because odd numbers are more aesthetically intriguing than even numbers.

“Grouping in threes is especially popular because odd numbers are appealing to the human eye,” he said in a TikTok.

“One can feel boring because there is no balance or visual interest, and even numbers like grouping in two or four can feel too stale and even a bit staged. Three just looks more dynamic and interesting.”

He went on to add that grouping in fives or sevens also works but can be more difficult to incorporate into one’s space than grouping three objects.

How to use the ‘Rule of Three’ in your home

Play with shape and scale

When decorating with a trio of similar objects (like ceramic vases on a shelf), varying the shape and scale of each item creates depth and interest in that space. Incidentally, the same concept applies when playing with three entirely different items (or clusters of items).

For example, if you are styling a coffee table, try to vary the proportions of your pieces, such as a tray (low and flat), a candlestick holder (tall and slim) and a small stack of coffee table books (mid-height with width and depth) for a dynamic effect.

Try a trio of textures

Grouping textures in threes is a great way to imbue a space with subtle visual interest. The space doesn’t have to be limited to three textures, of course, but the idea is to have only three primary ones. Think: a coastal living room emphasizing linen upholstery, plywood furnishings and jute accents or a Japanese-inspired bathroom with cypress wood fixtures, terracotta tiles and linen bath towels and mats.

Keep it to three core colors

As with textures, you can certainly have more than three colors in a space, but focusing on three core colors works to draw the eye without overwhelming it. To make it even simpler, you can employ the 60-30-10 color rule, which aligns perfectly with the ‘Rule of Three’. In the 60-30-10 rule, 60 percent of a room features one color, 30 percent comprises a secondary color, and 10 percent features an accent color.

Without getting too fixed on percentages — after all, it’s just a guide — in a bedroom, this could look like the walls, bedding and floors sharing the main color (with slight variations in tone or shade to avoid flatness), the bedside tables and vanity in the secondary color, and the remaining color featuring in lighting, small décor items and accent furniture.

Focus on furniture arrangements

Utilizing the ‘Rule of Three’ for furniture arrangements can help define a room and minimise any awkward gaps. As with small decorative objects, create dynamism via shape and scale when arranging pieces, such a large couch, round accent chair and coffee table that mixes both curved and straight lines.