2700 K to 6500 K on the Kelvin Scale

A table of the kelvin bands from 2200 K to 7000 K, what each looks like, and where the sources attach them.

Phosphor white LEDs span 2200 K to 7000 K, so every value in that range is available off the shelf. Warm white is 2700 K — the colour of a tungsten lamp at about 2700 K, yellow.

Daylight sits between 5500 K and 6500 K, and D65 / sRGB use 6500 K. D50 is the 5000 K standard; the upper end of the phosphor LED range reaches 7000 K.

In interiors, warmer (lower colour temperature) light is used in public areas to promote relaxation, while cooler (higher) light is used to enhance concentration, for example in schools and offices. The kelvin value changes the feel of the room without changing how much light it receives: the same lumens at 2700 K and at 6500 K light the room equally.

Note the inverted naming between physics and art: in physics, higher kelvin means a hotter, bluer source; in interior design, "warm" describes the lower-kelvin yellow light and "cool" describes the higher-kelvin blue light. Both usages are standard, and the package always prints the kelvin number so you can read past the word.

Choosing a band is therefore a use decision. Pick 2700 K for living rooms and other relaxation areas, 4000 K as a neutral middle, and 6500 K where daylight-like light supports concentration.

• 2200 K — warmest end of the phosphor LED range.
• 2700 K — warm white, tungsten yellow.
• 4000 K — neutral middle, common in work areas.
• 5000 K — D50 standard.
• 5500–6500 K — daylight band.
• 6500 K — D65 and sRGB reference.
• 7000 K — upper end of phosphor white LEDs.

Further reading

• Lumens Each Room Needs, Calculated from Lux
• CRI and Flicker: Judging a Lamp Before You Buy