The Biggest Living Room Design Mistake, According to Designers

Hint: It has to do with your sofa choice.

Apr. 17, 2026 at 6:51pm

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A brightly colored, high-contrast silkscreen print of a single, iconic living room sofa object repeated in a tight grid pattern, utilizing flat, vibrant, and unnatural neon color palettes overlapping with heavy black photographic outlines to turn an everyday furniture item into modern pop art.Designers warn that failing to properly measure living room dimensions before purchasing a sofa can lead to an unbalanced, uncomfortable, and dysfunctional space.Ellerslie Today

Designers warn that the most common living room design mistake is not properly measuring the space before purchasing a sofa. This can lead to a sofa that is either too large and overwhelms the room, or too small and looks underwhelming. Failing to account for the sofa's dimensions can also result in blocked walkways, an inability to fit the sofa through the door, and an overall unbalanced and uncomfortable living space.

Why it matters

The sofa is often the focal point and largest piece of furniture in a living room, so getting the scale right is crucial for creating a cohesive, functional, and visually appealing design. Designers emphasize that measuring the space thoroughly before buying a sofa can prevent costly mistakes that throw off the entire room's balance and flow.

The details

Designers explain that a sofa that is too large will overwhelm the space, crowding out other furniture and making the room feel tight and uncomfortable. Conversely, a sofa that is too small will look underwhelming and out of proportion, leaving the room feeling unfinished. Beyond just fitting the dimensions of the room, the sofa also needs to be able to physically fit through doorways, hallways, and stairwells to make it into the living space. Failing to account for these entry points can result in a sofa that simply cannot be moved into the home. Designers recommend mapping out the ideal sofa footprint with painter's tape, leaving 18 inches between the sofa and coffee table, and considering both the horizontal and vertical scale of the room.

  • Designer Cathryn Erickson of Cathryn Lindsey Design notes that measuring the space is a crucial first step before purchasing a sofa.

The players

Cathryn Erickson

A designer at Cathryn Lindsey Design who emphasizes the importance of measuring a space before buying a sofa.

Katie Lindquist

An interior designer at Katie Lindquist Interiors who says skipping the measurement step "almost guarantees regret" when it comes to a sofa purchase.

Fariha Nasir

A designer and DIY expert who explains that proper scale is what makes a room feel thoughtfully designed.

Laura Lubin

An interior designer at Ellerslie Interiors who notes that the sofa is often the largest piece in a living room, so its dimensions must be right.

Jamie Lyn Smith

The founder of Smith Home Studios, who says an oversized sofa can make a room feel tight and uncomfortable.

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What they’re saying

“Without measuring, you risk buying something too big that overwhelms the space or too small that leaves the room feeling unfinished.”

— Cathryn Erickson, Designer, Cathryn Lindsey Design

“Skipping that step almost guarantees regret, no matter how beautiful the sofa itself may be.”

— Katie Lindquist, Interior Designer, Katie Lindquist Interiors

“When the scale is off, the whole space suffers.”

— Fariha Nasir, Designer and DIY Expert

“A sofa that's too large will overwhelm the space, crowding side tables against the walls and making entry points feel tight and uncomfortable.”

— Jamie Lyn Smith, Founder, Smith Home Studios

“Beyond just fitting the room, you also need to consider doorways, staircases, and elevators.”

— Laura Lubin, Interior Designer, Ellerslie Interiors

What’s next

Designers recommend thoroughly measuring the living room space, including the ceiling height and all entry points, before purchasing a sofa. They advise using painter's tape to map out the ideal sofa footprint and leaving at least 18 inches between the sofa and coffee table to ensure proper flow and functionality.

The takeaway

Properly measuring the living room space before buying a sofa is crucial to avoid costly design mistakes. An incorrectly sized sofa can overwhelm or underwhelm the room, disrupt the flow of movement, and even prevent the piece from fitting through the door. By taking the time to carefully assess the dimensions, designers say homeowners can ensure their sofa purchase enhances the overall living room design rather than detracting from it.