What is colour temperature (Kelvin)?

Colour temperature describes the colour of white light on the Kelvin scale. Lower values (around 2700 K) look warm and yellowish, middle values (around 4000 K) look neutral white, and higher values (around 6500 K) look cool blue-white. It describes the colour of the light, not its brightness.

What is the difference between warm white and cool daylight?

Warm white (2700–3000 K) is yellowish like a traditional bulb and feels relaxed. Cool daylight (around 6500 K) is blue-white and crisp. Both can have the same brightness. The difference is the colour of the light, not the light output. Brightness is given in lumens, separately.

Which light colour is best for which room?

Common practice: warm white (2700–3000 K) for bedrooms and living rooms, cool white (around 4000 K) for kitchen counters and bathroom mirrors, and 4000–5000 K for study and work areas. Keep lamps within one colour family inside a room.

Tools · Lighting

Every light colour, live, from candlelight to daylight.

Every light has a colour, measured in Kelvin, from the warm orange of a candle (1000 K) to the blue-white of a north sky (12000 K). Slide to see any value, pin one to compare against another, and use the room guide below to decide what to buy.

4000 K Cool White

1000 K · warm 12000 K · cool

Screens can only approximate lamp light, so the colours here are representative, not calibrated. For a final call, try one lamp in the actual room.

Reading the box

What the label on the box means.

Warm White 2700–3000 K

Yellowish, like a traditional bulb. Relaxed, cosy light for winding down.

Cool White ≈ 4000 K

Neutral white, clean without feeling harsh. The middle ground, made for task areas.

Cool Daylight ≈ 6500 K

Blue-white and crisp. Looks the “brightest” of the three, though the colour doesn’t change actual light output.

Room by room

Which light colour for which room.

Space	Works well	Why
Living room	2700–3000 K	Warm and relaxed for evenings.
Bedroom	2700 K	The warmest of the standard choices, easy on the eyes before sleep.
Kitchen counters	4000 K	Neutral task light; food colours stay true.
Study / home office	4000–5000 K	Cooler light reads as alert and focused.
Bathroom mirror	4000 K	Neutral white keeps skin tones honest.
Shop displays	4000–6500 K	Match to the merchandise: warmer for wood and food, cooler for electronics and whites.
Security / parking	5700–6500 K	Crisp, high-visibility light for outdoor areas.