Watts used to be the go-to number for choosing a bulb, but watts only measure energy used — not brightness. Since LEDs use far less power than old incandescent bulbs for the same light output, lumens (not watts) are now the number that actually tells you how bright a bulb or fixture is.
Lumens vs watts: what’s the difference?
- Lumens measure the total amount of visible light a bulb produces — this is what tells you how bright it will actually be.
- Watts measure how much electricity the bulb consumes. A modern LED needs far fewer watts than an old incandescent bulb to produce the same number of lumens.
As a rough reference, a 60W incandescent bulb produces around 800 lumens — a comparable LED bulb typically only needs 8–9W to produce the same brightness.
How many lumens per room?
A helpful starting point is lumens per square metre of floor area, adjusted for how the room is used:
- Living room: ~150–300 lumens/m² (general ambient lighting, layered with lamps)
- Bedroom: ~100–200 lumens/m² (softer, relaxing light)
- Kitchen: ~300–400 lumens/m² (brighter, task-focused lighting for food prep)
- Bathroom: ~300–400 lumens/m² near mirrors and vanity areas
- Study / home office: ~300–500 lumens/m² to reduce eye strain during close work
These are general guidelines rather than strict rules — darker wall colours, larger rooms, and rooms with little natural light generally benefit from being lit slightly brighter than the ranges above.
Layer your lighting
Rather than relying on one single bright ceiling light, most rooms feel more comfortable with layered lighting: a main ceiling or downlight for general brightness, plus a lamp or accent light for softer, adjustable mood lighting in the evening.