SetMatcher
How your rating works

How your rating is calculated, step by step.

Your rating answers one question: how surprising was that result? It is worked out the same way for everyone, from the matches both sides confirmed, and nothing about it is hidden.

Everyone starts at 500. After 15 matches your rating has settled, and paying for anything never changes it.

Everyone starts at
500
Matches it settles over
15
It never falls below
0
Three numbers to know.

What the number is

One number, on the same scale for everyone. You start at 500, however well you already play, and your results move you from there.

The scale is chess's, divided by 3. Chess calls 1500 an ordinary club player; here that is 500. One point here is therefore worth 3 chess points, and a rating that moves by a point has moved by 3 in chess terms.

500 stays the middle of the field by itself: what one player gains is almost exactly what the other loses, so a group spreads out without its middle drifting far from 500.

The level shown next to a name is the same number in bands: 319 and below is level 1, every 40 points is one level higher, and from 640 it is level 10. A new player is level 6, at 500, because that is where everyone starts, and results sort out the rest.

One rating per sport, and per discipline

7 sports, each played as singles, doubles and mixed doubles, so there are 21 ladders one person can stand on, each with its own number and its own history.

A padel player is not a squash player, and a good doubles partner is not always a good singles player. One number across all of it would say less about each of them than the separate ones say about any one. It also means taking up a new sport costs you nothing: you start that ladder at 500, and your others never notice.

In doubles the pair is rated as one side, at the average of the two partners' ratings on that ladder, and each partner's own number then moves by what the result was worth to them. Playing with somebody stronger does not lend you their rating; it changes what was expected of the pair.

What moves it, and by how much

Only the gap between the two sides, the result, and how one-sided it was. Before a ball is hit the gap already says what share of the match each side is expected to take; afterwards, whoever beat their share gains and whoever fell short of it loses.

A gap of 133 points leaves the underdog about 9% of the match. Twice that, 267 points, leaves about 1%. Chess works the same way at 400 and 800 points, on a scale three times as big.

The share of a match the stronger player is expected to take, by the gap between the two ratings.
Gap in pointsThe stronger player's shareHow even a match
050%Even match
1054%Even match
2561%Close
5070%A stretch
8080%A stretch
10085%Long odds
13391%Long odds
26799%Long odds

Four example matches, calculated exactly the way your rating is. Everyone in them has played more than 15 matches, so nobody gets the bigger steps for new players described further down.

Four worked matches: the two ratings, the games, the expected share, the margin multiplier, and what each side's rating did.
The matchWinner beforeLoser beforeGamesWinner's expected shareMargin ×Winner movesLoser moves
Two players rated alike 50050012–850%1.10+9.5−9.5
The favourite wins 62048012–892%1.10+1.3−1.6
The favourite loses 48062012–88%1.10+17.8−15.1
The same even match, won to love 50050012–050%1.50+12.9−12.9

The two players always move in opposite directions, and when they are rated the same they move by exactly the same amount: what the winner gains, the loser gives up. When their ratings differ, the amounts differ slightly, because the steps get smaller as a rating climbs (see below) and the two players are at different points on that curve.

Why a big win is worth more than a narrow one

Every match is multiplied by how one-sided it was, between 1.0 for a result that hung on nothing and 1.5 for a whitewash. A win is a win either way; the multiplier only says how much evidence it is.

It is counted in the smallest unit each sport decides on: games in tennis, padel and beach tennis, and rally points in badminton, squash, pickleball and table tennis. Units from different sports are never compared, because a tennis game and a badminton point are nothing alike, so each sport’s rating uses its own units.

It stops at 1.5, and that limit matters. Without it, one afternoon where somebody could not miss would outweigh a season of close matches, and the scoreline says far less about strength than the result does. A match that could have gone either way counts 1.0 time, and a match won without losing a single unit counts 1.5 times, never more.

Why a new player's rating moves faster

For your first 15 matches in a sport and discipline, every step is bigger: twice the normal size in your first match, then a little less each time, until it is back to normal at match 15. The same win, at four points along the way:

How much larger a new player's step is, and what one even, narrow win moves at each point of that run.
Matches already playedStep ×That win moves
02.00×+19.0
51.67×+15.8
101.33×+12.7
151.00×+9.5

Your first rating is a guess, and 15 matches is roughly how long it takes for your results to say more about you than the starting number does. After that the steps go back to normal, because a rating that jumped around every week would tell you about last Tuesday rather than about the player.

Why the ratings of strong players move less

The step size gets smaller as a rating climbs. At the bottom of the scale it is 24, and by 800, which is chess’s grandmaster level of 2400 on this scale, it has halved to 12. It shrinks smoothly, not in jumps, and it never reaches zero.

How the step size falls as the rating climbs, and what one even, narrow win moves at each of them.
RatingStep sizeThat win moves
024.0+13.2
25021.9+12.0
50017.3+9.5
80012.0+6.6
12007.4+4.1

A high rating has more results behind it, so each new result should change it less: the number has been earned and is being defended rather than found. That is also why a climb slows down instead of stopping: the step keeps shrinking without ever reaching zero, so nobody gets stuck.

Where it stops

A rating never falls below 0. This is a set limit, not something the calculation produces on its own.

Without it, a long losing run could push a rating below zero, which means nothing to anyone and feels like a punishment rather than a measurement. So a loss that would take someone under 0 takes them to 0 instead, and the winner still gets their full gain. It rarely happens, and it is the only exception to the calculation.

What does not move it

Five things never change your rating.

  • A result nobody has agreed with yet. A score sits unconfirmed until the other side accepts it or the time to object runs out; no ladder moves before then.
  • A walkover, a default or a no-show. The win stands and the draw moves on, but nobody played, so nobody's rating changes. A retirement is different: that match was played, and it counts.
  • A friendly match where one side was given a head start. The score includes points nobody won, and the result came from a contest that was tilted on purpose, which is what a head start is for, and exactly why it says nothing about who is stronger. A club ladder played with a handicap still moves, but ratings do not.
  • Anything anyone pays for. No plan, pass or fee moves a rating, a draw, a seeding or a match suggestion by a single point, in any direction, for anyone. There is no paid version of the ladder, and there never will be.
  • And a mistake leaves no mark. When a result is corrected, every rating that result touched is worked out again from that match onward, so the ladder ends up exactly where it would have been if the right score had gone in the first time.

Your first match is one tap away.

Join a group, play, enter the score. The ladder, the draw and the season keep themselves up to date.