Planning guide

Bathroom Mirror and Lighting Guide

The mirror and the light over a vanity are usually chosen last and installed first, which is exactly backwards. Both depend on the counter height, both need power roughed in before the wall is closed, and the lighting decision determines whether anyone can actually see their face. Three coordination points, all cheap on a drawing and expensive afterwards.

The short answer

Quick Reference

Size the mirror to the vanity, not to the wall.
Center the mirror on the basin, not on the cabinet, if they differ.
Side lighting at face height beats a downlight over the basin, always.
Power positions must be roughed in before tiling.
Reference every height to finished floor level, not to the substrate.

A wall-mounted vanity in a residential bathroom

Start here

Three Things to Get Right

Mirror and lighting planning reduces to three decisions, and all three reference the vanity rather than the room.

How big the mirror is and where it sits, which is a proportion question. Where the light comes from, which is a physics question with one correct answer. And when the power and fixings are installed, which is a programming question and the one most often missed.

Mirror size and position, referenced to the vanity
Light position, which decides whether faces are lit or shadowed
Rough-in timing, which must precede tiling
All heights referenced to finished floor level
On projects, one datum applied consistently across rooms

Sizing and Positioning the Mirror

A mirror should relate to the vanity below it, not to the wall it hangs on. The common convention is a mirror narrower than the vanity by a small margin on each side, which frames it and avoids the mirror appearing to overhang.

Height is more useful expressed as a range than as a single number. The bottom edge typically sits a short distance above the countertop or backsplash, and the top should be high enough that a tall user sees the top of their head. Working from the counter upward rather than from the ceiling downward produces a better result.

Centring is where the mistakes happen. Center the mirror on the basin rather than on the cabinet where those differ, because people stand at the basin. On a double vanity, two mirrors centered on the two bowls almost always work better than one wide mirror centered on the cabinet.

Mirror narrower than the vanity, with a margin each side
Bottom edge just above the counter or backsplash
Top high enough for the tallest regular user
Center on the basin, not the cabinet, when they differ
Two mirrors usually beat one on a double vanity

Where the Light Should Come From

A wall-mounted bathroom vanity in a finished bathroom

This has one correct answer and it is widely ignored. Light for a face should come from the sides at roughly face height, not from above.

A downlight placed over the basin lights the top of the head and casts the eye sockets, nose and chin into shadow, which is precisely the opposite of what someone shaving or applying makeup needs. Side lighting at face height fills those shadows and produces even illumination.

The practical implementations are wall sconces flanking the mirror, vertical strips beside it, or a backlit mirror where the light emerges around the perimeter. All three work. A single fitting above the mirror is the weakest option and is common because it is the easiest to wire.

Color temperature is worth a moment too. Something in the neutral range renders skin tones reasonably; very warm light makes it hard to judge makeup and very cool light is unflattering and clinical.

Side lighting at face height, not downlighting from above
Wall sconces flanking the mirror, or vertical strips beside it
A backlit mirror achieves the same effect around the perimeter
A single fitting above the mirror is the weakest arrangement
Choose a neutral color temperature for reasonable skin rendering

Rough-In and Coordination

A run of integrated basin vanities in a hotel bathroom

Everything above has to be decided before the wall is closed, which puts it early in the construction program rather than in the fit-out phase where mirrors and lights are usually chosen.

Power for a backlit or illuminated mirror needs a cable in the right place, at a height derived from the mirror size and position, which is derived from the counter height. Sconces need their own positions. Heavy mirrors and mirror cabinets need fixings that a plasterboard wall cannot provide alone.

For a project with repeat rooms, settle this once as a room-type drawing and hold it. Mirror center, sconce centers, cable positions and fixing points all measured from finished floor level and from the basin centerline, so that every room is set out the same way regardless of who installs it.

The single most common error is referencing heights to the substrate rather than to the finished floor. Tiling commonly adds 15 to 25 mm, and a room set out before tiling will have everything sitting low by that amount.

Cable and fixing positions must precede boarding and tiling
Derive mirror and light heights from the counter height
Provide backing for heavy mirrors and mirror cabinets
Reference everything to finished floor level, not substrate
On projects, one room-type drawing applied across all rooms

Common questions

Mirror and Lighting Questions

How wide should a bathroom mirror be?

Narrower than the vanity, with a margin on each side so it appears framed rather than overhanging. Size it to the vanity rather than to the wall, and on a double vanity two mirrors centered on the bowls usually work better than one wide mirror.

How high should a mirror be above a vanity?

Work upward from the counter rather than down from the ceiling. The bottom edge sits a short distance above the counter or backsplash, and the top should be high enough for the tallest regular user to see the top of their head.

Where should bathroom vanity lighting go?

At the sides, at roughly face height. A downlight above the basin lights the top of the head and shadows the eyes, nose and chin. Wall sconces flanking the mirror, vertical strips beside it, or a backlit mirror all solve this.

Are backlit mirrors better?

They provide even perimeter lighting, which addresses the shadow problem well, and they remove the need for separate fittings. They require power roughed in at the correct position before the wall is closed, which is the main planning constraint.

Should the mirror be centered on the vanity or the basin?

On the basin, where they differ, because that is where people stand. Centring on the cabinet looks correct on a drawing and wrong in use when the bowl is offset.

What is the most common mistake?

Referencing heights to the substrate rather than to the finished floor. Tiling adds 15 to 25 mm, so a room set out before tiling has the mirror, lights and outlets all sitting low by that amount.

A bathroom vanity set in a boutique hotel

In short

Plan It With the Vanity, Not After

Size the mirror to the vanity and center it on the basin. Put the light at the sides at face height, because a downlight over the basin shadows exactly the parts of a face people need to see.

Then get the rough-in right: cables and fixings before boarding, heights derived from the counter and referenced to finished floor level. On a project, settle one room-type drawing and apply it everywhere, so every room is set out identically regardless of who installs it.

Mirror narrower than the vanity, centered on the basin
Side lighting at face height beats downlighting, always
Backing and cables before boarding and tiling
Reference all heights to finished floor level
One room-type drawing, applied consistently

Planning a bathroom package?

Talk to WNS Global

Tell us the vanity sizes and room types and we will provide the counter heights, mirror sizes and the setting-out dimensions from finished floor level, so the electrical rough-in can be coordinated before the walls are closed.