Elo ratings for women's football
There is no official or unofficial ranking of women's clubs in Europe, let alone the world. This is one, built on the same Elo system that underlies FIFA's national-team ranking.
Since the official FIFA ranking of national teams rests on the Elo rating system, we used the same system to rate European clubs.
The K factor
For domestic league matches, K follows the UEFA women's Champions League association coefficient rankings: 30 for top-tier countries (Germany, France, Sweden and England), 25 for the second tier (Spain, Russia, Italy and Denmark), 20 for the third (Czech Republic, Austria, Scotland, Norway and Switzerland) and 10 for everyone else. Champions League matches use 30 in qualifying and 60 in the main stage.
Starting ratings
Clubs begin at 1500 in top-tier leagues, 1400 in the second tier, 1350 in the third and 1250 elsewhere. Both the K factors and the starting ratings vary by country for the same reason: the gap between women's football in different countries is still wide enough that a single starting point would badly overrate clubs from the lower tiers.