Expected win chance = 1 ÷ (1 + 10^{((rival Elo − your Elo) ÷ 400)})

Elo change = K × (result − expected win chance). A win is 1, a draw is 0.5, and a loss is 0.

For your first 10 matches after placements, completed defeats cost half the usual Elo. Wins stay the same. Surrenders and disconnect losses take the full loss and still count as a match.

Voided matches do not change Elo. Divisions I → II → III follow your rating; points are never spent on promotion.