How the skill rating works

Every player starts on 1500. After each completed game the two teams are compared on their average rating, that comparison produces an expected result, and the points that change hands are the gap between the expected result and what actually happened.

Ratings are club-local. The same person in two clubs has two independent ratings, and they are never merged or averaged, because the only thing a rating means is how someone compares to the people they actually play against.

The K-factor sets how much a single result can move a rating. New players move faster so they reach a realistic figure quickly; settled players move more slowly so one bad night does not undo a season.

The figure applied to a game is the average of the four players' individual K-factors, so a game between four settled players moves less than a game involving two newcomers.

Games played counts every format, including any that do not themselves move ratings — a club that has switched singles off still sees those games advance a player through the K tiers.

A doubles game has one result and four players, so the calculation has to decide who the result belongs to. It belongs to the pair.

1. Each side's strength is the average of its two players' ratings going into the game, after every earlier game has counted.
2. The expected result comes from comparing those two averages.
3. The K-factor is the average of all four players' individual K-factors.
4. Both players on the winning side gain exactly the same amount, and both on the losing side lose exactly that amount.

There is no attempt to credit one partner more than the other. A 1700 player and a 1300 player on the same side move by the same number of points, whoever carried the game — the score cannot say.

Someone who has not played for the club before starts on 1500. Until they have played enough games to settle, results involving them are judged against that starting figure rather than a measured one.

The calculation uses each player's rating going into the game. Team balance, when a club turns it on, compares the ratings players joined the session with instead, so the two can differ late in a long night.

Your pair averages 1490. The pair across the net averages 1580. The four of you are mid-experience, in the 10-to-29 game bracket.

Beating the stronger pair is worth more than beating an equal one, and losing narrowly to a stronger pair still costs points — the margin is not a consolation. These figures are computed by the same function the app runs after a real game, not written into this page, so they cannot drift from the engine.

The rating formula is versioned, and every session is stamped with the version that was current when it was created. History is replayed against its own stamp rather than against today's rules.

The current formula is the third. It followed a volatility review that found the previous version's use of score margin was making ratings swing on results that were not meaningfully different, and it produces swings roughly 30% smaller than the original on the same scale.

Because stamps are per session rather than per club, a club that has been running for several seasons holds history under more than one formula. Season boards replay from a common baseline so they remain internally comparable; the all-time board is the accumulated ledger and is not re-derived.

See also Seasons, the points race and awards · Achievements overview