Elo rating
also: tennis Elo · player rating
Our rating for every player, moved after each completed match by how surprising the result was.
new = old + K x (result - expected); expected = 1 / (1 + 10^((opponent - player) / 400)); K = 250 / (matches + 5)^0.4Every player starts at 1,500. After each completed match the winner takes points from the loser, more for beating a stronger player than a weaker one. K, the size of the step, falls as a player plays more, so newcomers find their level quickly and established ratings move slowly; the schedule is the one FiveThirtyEight published for tennis.
It is computed per tour from every completed singles match in the data since 2007, main draw and qualifying, in the order they were played. Walkovers, defaults and retirements are not rated.
Ratings are ours and are not the ATP or WTA ranking, which counts points from the last 52 weeks of tournaments. A rating says how strong a player is now; a ranking says how much they have won lately.
Players who started before 2007 begin at 1,500 in 2007 and spend their first season catching up. Treat 2007 and 2008 ratings with care.
Where to get it
Related
Elo rating from the API
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