A bathroom has two lighting jobs, and only one of them is about the room. The vanity is a face lighting problem, and it is decided far more by where the fitting sits than by how many lumens it emits.
The general method is in how many lumens a room needs.
The numbers
General bathroom light: 20–30 lumens per square foot.
Vanity: 50–80 lumens per square foot over the vanity area, or in practical terms 1,600–2,400 lumens at the mirror for a normal single vanity.
| Bathroom | General | Vanity |
|---|---|---|
| 40 sq ft | 800–1,200 lm | 1,600–2,400 lm |
| 60 sq ft | 1,200–1,800 lm | 1,600–2,400 lm |
| 100 sq ft | 2,000–3,000 lm | 1,600–2,400 lm (single) |
Note that the vanity figure barely changes with room size — it depends on the mirror, not the floor.
Position is the whole problem
A light above the mirror shines down on your face. Everything that projects — brow, nose, chin — casts a shadow on what is beneath it. Making that fitting brighter deepens the shadows.
Light from both sides at roughly face height fills those shadows from the left and the right, which is why it is the standard for makeup mirrors and theatre dressing rooms and has been for a century.
In order of preference:
- Sconces or vertical fittings on both sides of the mirror, centred at roughly 60–66 inches from the floor, spaced so they sit just outside the mirror edges. This is the correct answer.
- A backlit or edge-lit mirror, which achieves something similar by wrapping light around the perimeter.
- A long horizontal fitting above the mirror, which is better than a small one but still lights from above.
- A single downlight in the ceiling in front of the mirror, which is the worst common arrangement and unfortunately the most frequently installed.
If the wall genuinely will not take side fittings, a wide diffused fitting above the mirror plus a bright general layer is the compromise — the room bounce fills some of the shadow.
Colour rendering matters here more than anywhere
CRI — colour rendering index — measures how accurately a light source shows colours against a reference. It is a separate property from colour temperature.
In a bathroom, low CRI shows up as skin tones that look wrong and makeup that is applied to look correct under the bathroom light and then looks wrong in daylight.
Look for CRI 90 or above at the vanity, and pay attention to R9 if the manufacturer publishes it. R9 is the deep red component, it is not included in the headline CRI average, and it is the one that governs whether skin looks healthy or grey. A lamp can advertise CRI 90 with poor R9 and still render faces badly.
Colour temperature
3000 K to 3500 K is the usual recommendation for a vanity. Warm enough not to feel clinical, neutral enough that colours read close to daylight.
- 2700 K is pleasant for the room and slightly too warm for grooming — it flatters, which is exactly the problem if you are applying makeup you intend to wear outside.
- 4000 K and above reads accurately but feels cold, and in a small tiled room it can be genuinely unpleasant.
Match the two layers. General and vanity lighting at different temperatures looks wrong immediately, and a bathroom is small enough that you see both at once.
The other layers
General. A ceiling fitting at the room's target lumens. In a small bathroom this and the vanity between them are the whole installation.
Shower. A wet-rated recessed fitting if the shower is enclosed or separated enough that the general light does not reach it. This must be rated for the location — that is a code requirement, not a preference, and it varies by how close the fitting is to water.
Night. A bathroom is the room most often used in the middle of the night. A very low-level option — a dimmed circuit, a low nightlight, or a lit mirror at its lowest setting — is worth more than most of the rest of the specification.
What this page does not cover
- Electrical safety and zone requirements around baths and showers are code-governed, vary by jurisdiction, and are a job for a qualified electrician.
- Extraction and ventilation, which often shares a circuit with the lighting and has its own requirements.
- The general method and the room corrections are in how many lumens a room needs.
- Mirror and fitting sizing as a proportion of the vanity, which is an aesthetic question rather than a lighting one.
Two fittings either side of the mirror at face height, CRI 90 or better, 3000 K. The lumens are the easy part.