Scale and proportion: how do I pick the right furniture size?

Scale is how furniture fits the room. Proportion is how pieces fit each other. A good rule of thumb: fill about 60% of the floor with furniture and keep about 40% free, then size each piece against its neighbours.

Scale: furniture and the room

Measure the room first, including ceiling height, windows and doors.
Big room, bigger pieces: small furniture in a large room looks scattered.
Small room, fewer pieces at the right size: not many tiny ones.
Low ceilings: low, long furniture. High ceilings: tall bookcases, long curtains and pendant lights fill the height.
Draw pieces on the floor with tape to see their real footprint.

Proportion: pieces together

Common guides:

Coffee table: about two-thirds the length of the sofa, and about the height of the seat or slightly lower.
Side tables: close to the height of the sofa arm.
Rug: large enough for at least the front legs of all seats.
Art above a sofa: about two-thirds of the sofa's width.
Dining table: about 60 cm of edge per person, plus room for chairs to move.
Bed: at least 60 cm free on the sides you use.
Pendant over a table: about half to two-thirds of the table's width.

Visual weight

Two pieces of the same size can feel different. A sofa with thin legs and arms looks lighter than a solid block. Glass, open frames and raised legs feel lighter; dark colours and solid bases feel heavier. Use light pieces in small rooms, and balance one heavy piece with lighter ones around it.

Signs something is off

You can't walk around a piece comfortably.
One piece dominates and the rest look like toys.
The room feels empty even with furniture in it.
A rug or lamp looks lost.

Check sizes before you buy

Furniture looks smaller in a showroom. A 3D model of your room with real dimensions shows exactly how big each piece will be in your space.