GigaRatings is a points based rating system aimed at regional/national sports associations based on sound probability theory. Scales, constants and variables are set by the association. The algorithm used to calculate a player's new rating after playing a match is based on Professor Arpad Elo's algorithm used by the National Chess Federation.

It is based on the probabilities of winning or losing the match. If a player plays a much higher rated player, then his/her probability of winning that match is small. Thus, if he/she wins that match, then his/her rating is adjusted upward by a lot. On the other hand, if they lose that match, their rating is lowered only very slightly, if at all. Conversely, the higher rated player would have their rating lowered by a lot if they lost to the much lower rated player, but only raised by a little, if at all, if they win that match.

The math behind the algorithm is as follows:

WOR = Winner's old rating
WNR = Winner's new rating
LOR = Loser's old rating
LNR = Loser's new rating
K = constant
D = denominator
PW = Probability that the winner would win
PL = Probability that the loser would win

WNR = (WOR+K*(1-PW))
LNR = (LOR+K*(0-PL))
PW = (1/(POWER(10,(-(WOR-LOR)/D))+1))
PL = (1/(POWER(10,(-(LOR-WOR)/D))+1))