In noise mapping, the European Directive 2002/49/EC requires an estimation, to the nearest hundred, of the number of people living in dwellings that are exposed to different bands of Lden values in dB 4 m above the ground on the most exposed façade. Even though this methodology always overestimates the effects caused by noise, this estimation is accurate enough for detached or semidetached houses in urban areas. However, for large and tall buildings in urban configuration, this estimation could be confusing and even very vague. In fact, differences regarding the percentage of people affected by noise taken from an exact calculation and from European Directive criterion could be unacceptable. When façade noise map calculation is not possible, either due to being too time consuming or unavailability of software resources, estimating people affected by noise based on the nearest grid point approximation criterion is clearly preferable to the European Directive approach.