This table shows the correlation between the difference in Elo points and the probability of winning a game (in bold). So for example if a player has won 60% of her games against an opponent, she would be approximately 72 Elo points stronger. Conversely, a player that is 150 points weaker than his opponent, has only a 30% chance of winning a game.
.99 +677 .66 +117 .33 -125 .98 +589 .65 +110 .32 -133 .97 +538 .64 +102 .31 -141 .96 +501 .63 +95 .30 -149 .95 +470 .62 +87 .29 -158 .94 +444 .61 +80 .28 -166 .93 +422 .60 +72 .27 -175 .92 +401 .59 +65 .26 -184 .91 +383 .58 +57 .25 -193 .90 +366 .57 +50 .24 -202 .89 +351 .56 +43 .23 -211 .88 +335 .55 +36 .22 -220 .87 +322 .54 +29 .21 -230 .86 +309 .53 +21 .20 -240 .85 +296 .52 +14 .19 -251 .84 +284 .51 +7 .18 -262 .83 +273 .50 0 .17 -273 .82 +262 .49 -7 .16 -284 .81 +251 .48 -14 .15 -296 .80 +240 .47 -21 .14 -309 .79 +230 .46 -29 .13 -322 .78 +220 .45 -36 .12 -335 .77 +211 .44 -43 .11 -351 .76 +202 .43 -50 .10 -366 .75 +193 .42 -57 .09 -383 .74 +184 .41 -65 .08 -401 .73 +175 .40 -72 .07 -422 .72 +166 .39 -80 .06 -444 .71 +158 .38 -87 .05 -470 .70 +149 .37 -95 .04 -501 .69 +141 .36 -102 .03 -538 .68 +133 .35 -110 .02 -589 .67 +125 .34 -117 .01 -677