A common question we often get is: How do you calculate how many lumens = a certain kelvin. In short, these are two measurements that are not directly related. See our "Watts vs. Lumens vs. Kelvin" page. Kelvin is not a measure of brightness rather it is a measure of color temperature. If you are looking for brightness, the proper measurement to look for is lumens. In general though, 5000K or cool/daylight white will a appear brighter than 2700K all things being equal but this is due to the higher contrast of such light.