How to Calculate the
Right Mirror Size for Your Wall
Mirror sizing is one of the most common specification errors in interior design — and one of the most avoidable. These are the rules and formulas that get it right the first time.
A mirror should be 50–75% of the width of the furniture below it — or, on a bare wall, no wider than two-thirds of the available wall space. When in doubt, go larger rather than smaller.
Four Steps to the Right Size
Measure the furniture it will hang above
If the mirror is going above a console table, sideboard, bed, or sofa — measure the width of that piece first. This is your primary constraint. The mirror should not be wider than the furniture below it, and ideally sits at 50–75% of that width.
Measure the wall space available
Note the full width between any architectural constraints — corners, doorframes, windows, light switches. The mirror should leave breathing room on either side. A minimum of 15–20cm clearance on each side of the mirror is the general rule for a hung piece to read comfortably rather than crowded.
Determine the hanging height
The centre of the mirror should sit at approximately eye level — 155–165cm from the floor for a standard-height room with standing viewing. Above a piece of furniture, allow 15–25cm of clearance between the top of the furniture and the bottom of the mirror frame. This gap is critical — too small and the mirror appears to be resting on the furniture; too large and the relationship is lost.
Apply the proportion check
Step back and assess: does the mirror feel proportional to the wall, the furniture, and the room? A mirror that is too small is the most common error — it floats on the wall without authority and fails to do what a mirror should do: anchor the space, extend light, and complete the composition. When the arithmetic gives you a range, choose the larger end.
Proportions at a Glance
Diagram: correct mirror proportions above a console table or sideboard
Sizes for Specific Situations
120cm console → 70–90cm mirror
A console table is typically 100–130cm wide. The mirror should be comfortably within its width — a 90cm mirror on a 120cm console is ideal. Round or arched mirrors work particularly well in this position as the curved form softens the horizontal line of the table.
180cm sideboard → 100–120cm mirror
Sideboards are typically 160–200cm wide. A single large mirror at 100–130cm wide works well, or a pair of rectangular mirrors placed symmetrically above the piece. The pair approach gives more flexibility with sizing and creates a composed, gallery-like arrangement.
King bed → 120–150cm mirror
Above a bed, the mirror can go up to the full width of the headboard. A large rectangular or arched mirror in this position anchors the bed as the room centrepiece and creates a strong visual composition. Ensure the bottom of the mirror is at least 30cm above the headboard top.
3m wall → 160–200cm mirror
On a bare wall with no furniture reference, the mirror can be considerably larger. A floor-leaning oversized mirror on a 3m wall is not too large if it fills two-thirds or less of the wall width. The effect is architectural rather than decorative — it becomes a feature of the room.
What Goes Wrong — and Why
Too small — the most common error
A mirror that is under 50% of the furniture width below it looks like an afterthought. It floats disconnected on the wall and loses the proportional relationship that makes the arrangement work. When uncertain between two sizes, choose the larger.
Hung too high
Mirrors hung significantly above eye level reflect ceiling rather than the room — which defeats their primary purpose of extending light and space. The centre of the mirror should be at approximately 155–165cm from the floor regardless of ceiling height. High ceilings do not require high mirrors.
Insufficient clearance below
A mirror hung with less than 10cm of clearance above the furniture surface appears to sit on the piece rather than hang above it. The relationship collapses into visual confusion. A minimum of 15cm and ideally 20–25cm clearance gives the mirror room to read as a distinct hanging object.
Ignoring what the mirror reflects
A mirror reflects what is directly opposite it. Before finalising position, stand where the mirror will hang and look at what will be in view — the ceiling, the opposite wall, a window, or a cluttered corner. Positioning the mirror to reflect a window or a well-considered wall maximises its spatial effect. Reflecting a blank ceiling or a doorframe wastes the opportunity.
The Paper Template Method
Before ordering or purchasing a mirror, cut out its dimensions in kraft paper or newspaper and tape it to the wall at the intended hanging position. Live with it for a day. View it from sitting height, standing height, and from the room entrance. This simple step catches sizing and positioning errors that are obvious in three dimensions but invisible on a floor plan — and it costs nothing.
Need help specifying the
right piece for your space?
Bring your wall dimensions and we can advise on sizing, shape, and framing options to suit the room and the furniture it will sit with.