Elo calculator

Expected score and rating change for a single game with any K-factor.

Your rating

Opponent rating

Result

K-factor

Rated games played

Under 18

Rating change

+12.8

New rating about 1513. Expected score against a 1600 player: 36.0%. K = 20.

Outcome	Change	New rating
Win	+12.8	1513
Draw	+2.8	1503
Loss	-7.2	1493

Formula: expected score E = 1 / (1 + 10^{(opponent − you) / 400}); change = K × (score − E). FIDE caps the rating difference at 400 points for its tables; this calculator uses the raw formula, which differs by at most a point or two.