Although a European standardised calculation method for the capacity of eaves gutters exists since 2000, described in EN 12056-3, many countries still apply their own national method. In Belgium two methods are preferred besides the European one: a method described in the Belgian standard NBN 306, valid since 1955, and a method based on the French standard NF DTU 60.11.P3 (1988 and revised in 2013). However the calculation results according to these 3 methods differ significantly. To justify a generalised use of only one method, the Belgian Building Research Institute decided to verify which method is most valid. For this purpose, the capacities of commonly used eaves gutters in Belgian practice were measured in standardised conditions. This paper presents the measurement results which prove that calculating according to the European standard EN 12056-3 is the best choice for gutter dimensioning.