The higher the Kelvin rating (often expressed in K), the whiter the light will be.
Light bulb color temperature is represented in the unit of absolute temperature, Kelvin, noted by the symbol K. Household fixtures are commonly found in color temperatures on the Kelvin scale of 2700K (warm incandescent), 3000K (warm white halogen) and 3500K (household fluorescent).
Color temperatures higher than 3500K are typically used for commercial and hospital applications, as the light is bright and has a bluish daylight cast that can be harsh for home interiors; but task lighting may be useful at 4000K and above. When selecting new lighting for your home, be sure to take its color temperature into account to ensure you're making the right choice.
3000K: gives off a soft white glow, often yellow in appearance; best for living rooms, dining rooms, bedrooms and outdoor spaces
4000K: gives off a bright amount of white light; best for kitchens, offices, workspaces and vanities where task lighting is needed
5000K: gives off a bright amount of blue-white light, like that of daylight; best for display areas and work environments where very bright illumination is needed.