Updated June 1, 2026

The essential decorating rules to know

Most rooms do not fail for lack of taste, but for lack of proportion. You buy a sofa because it looks good in a photo, a table because you like it, a frame you hang wherever, and the room feels off without anyone knowing why. The good news: decorators do not follow trends, they follow numbered rules. And those numbers almost always give better results.

In this guide you will discover the essential rules that make a room work: the sofa and living room, the dining room, the bedroom, lighting and frames, then colors and materials. With the right numbers to remember each time.

The sofa: the centerpiece of the living room

Design idea: a room that follows the essential decorating rules

Everything starts with the sofa. Its width should be about two thirds of the wall length: a 3 meter wall calls for a sofa of 2 meters maximum, a 2.50 meter wall for a sofa of 1.65 meters maximum.

Around it, a few distances change everything:

• Coffee table: 40 to 50 cm from the sofa, close enough to set down a glass, far enough to walk past.
• Coffee table height: the same as the sofa seat (plus or minus 5 cm). This is the rule everyone ignores.
• Rug: it extends 20 cm beyond each side of the sofa, or at the very least the front legs of the sofa rest on it. Never a rug floating in the middle.
• TV distance: 1.5 times the screen diagonal. A 140 cm TV calls for a viewing distance of 2.10 meters.
• Walkway: 80 cm minimum between the sofa and the piece facing it. Below that, no one passes comfortably.

The dining room: every centimeter counts

A poorly sized table either smothers the room or crams the guests. The benchmarks:

• Space per person: 60 cm of width minimum per guest. A table for 4 is at least 120 x 80 cm, a table for 6 at least 180 x 90 cm.
• Chair-to-wall clearance: 80 cm between the edge of the table and the wall (60 cm for the chair, 20 cm to walk). Below that, no one passes behind.
• Table width: 50 % maximum of the room width. In a 3 meter room, the table is 1.50 meters at most.
• Pendant light: 70 to 80 cm between the table and the bottom of the pendant, centered on the table. Above an island or a large table, always an odd number of pendants, spaced 60 to 75 cm apart. One or three, never two.

The right reflex: test with chairs before ordering the table.

The bedroom: balance around the bed

In the bedroom, everything comes down to the relationship between the bed and the space around it:

• Headboard: bed width plus 20 cm on each side. A 140 cm bed calls for a 180 cm headboard.
• Nightstands: at mattress height (plus or minus 5 cm), 30 cm wide minimum.
• Walkway: 60 cm minimum on each side of the bed. If the room is small, push one side against the wall.
• Rug: it extends 60 to 90 cm beyond each side of the bed, so you step onto it when getting up.
• Frame above the bed: center at 150 to 160 cm from the floor, width equal to two thirds of the headboard, never wider than the bed.
• Bedding: 3 to 5 cushions in an odd number, at least 2 materials, and a throw that runs about one third of the bed length.

Lighting and frames: the details that change everything

A single ceiling light gives flat lighting. For atmosphere, plan three levels of light per room: at the top the ceiling light, in the middle a wall light or floor lamp, at the bottom a table lamp.

To place each source and each frame well:

• Wall lights: center at 160 to 170 cm from the floor, identical throughout the room.
• Floor lamp: bottom of the shade at seated shoulder height, so 110 to 120 cm from the floor.
• Wall frames: center at 145 to 150 cm from the floor, at eye level. Above a piece of furniture, 15 to 25 cm of gap.
• Gallery wall: 5 to 7 cm between each frame, starting with the central one and aligning the centers, not the edges.
• Mirror: one large one per room, covering two thirds of the wall height, facing a window to double the light, never facing a door.

To go further on what drags a room down, see our decorating mistakes to avoid.

Colors and materials: harmonize without missing

The reference ratio is the 60-30-10 rule: 60 % dominant color (walls, floor, large furniture), 30 % secondary (textiles, curtains), 10 % accent (cushions, objects). We cover it in detail in our dedicated guide to the 60-30-10 rule.

The rest comes down to a few simple benchmarks:

• Colors: three maximum per room, that is two neutrals and one strong color (white, wood, terracotta for example).
• Materials: at least three different ones, such as wood, fabric and metal, or linen, ceramic and glass. Variety creates richness.
• Cushions: 3 to 5, always an odd number, 2 to 3 sizes, at least 2 materials (linen and velvet for example).
• Curtains: rod 15 to 20 cm above the window, length down to the floor, fabric width equal to 1.5 times the window width. Never mid-calf.
• Plants: 2 to 3 per room, in three sizes (one large on the floor, one medium on a piece of furniture, one small on a shelf).

The palette is decided before buying, not after.

The proportion mistakes that kill a room

A few faults come up again and again:

• Buying a sofa without measuring the wall, the number one cause of regret.
• Picking a coffee table at random, without checking the seat height.
• Hanging frames too high (2 meters instead of 1.50).
• Laying a rug too small that floats in the middle of the living room.
• Forgetting the 80 cm walkway between pieces.
• Installing the pendant too high above the table.
• Buying everything in the same color and the same material.

Test these rules on your room

Reading the numbers is a start; seeing them applied to your own room is more convincing. With Shopia, you photograph your room, pick a style and a palette, and get a realistic render in a few minutes. You can compare before and after, adjust the proportions and try several combinations before measuring, repainting or buying anything.