Chess rating expected score calculator

Calculate player expected fraction of one point per game and opponent expected fraction of one point per game with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use player expected fraction of one point per game and opponent expected fraction of one point per game to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Player rating
1600
Opponent rating
1800
Supplied base-10 logistic rating scale
400
Games for expected-point scenario
10
Player expected fraction of one point per game
0.240253
Opponent expected fraction of one point per game
0.759747
Player expected points across supplied games
2.402531
Player rating minus opponent rating
-200

Try another scenario

Player rating
1600
Opponent rating
1600
Supplied base-10 logistic rating scale
400
Games for expected-point scenario
10
Player expected fraction of one point per game
0.5
Opponent expected fraction of one point per game
0.5
Player expected points across supplied games
5
Player rating minus opponent rating
0
Calculation method

Calculation method

Player expected fraction of one point per game

1/(1+10^((opponent−player)/scale)).

Opponent expected fraction of one point per game

One minus player score expectation.

Player expected points across supplied games

Game count×expected fraction; linear expectation does not determine win/draw/loss probabilities separately.

Player rating minus opponent rating

Supplied player−opponent rating.

Symbols and units
a
Player rating
b
Opponent rating
c
Supplied base-10 logistic rating scale
d
Games for expected-point scenario

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • A smooth Elo-style logistic expected-SCORE model at a supplied scale, not a calibrated win probability or official FIDE rating-table calculation. A score expectation does not identify separate win and draw chances.
Are these inputs private?

These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.

Further reading

FIDE: rating-system background; this worksheet uses a smooth supplied-scale logistic model, not FIDE table processing ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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