ELO Rating Calculator

Enter the old rating from:
BZFlag CTF League / Teams

Formula used by the BZFlag CTF League (simplified ELO-Rating):
» Using the old ratings oldA and oldB, the win probability for team A is calculated:
prob = 1.0 / (1 + 10 ^ ((oldB-oldA)/400.0))
» he change in the ratings is then calculated by:
score = 1 if A wins, 0.5 for draw, 0 if B wins
diff = 50*(score-prob)
» After that some rounding magic to integer is applied and the new ratings are calculated:
newA = oldA+diff, newB = oldB-diff