What is an Elo rating in chess?

Elo is a numerical score that estimates your strength relative to other players. Higher Elo means stronger play. New players at Chess Global League start at 1200.

How is Elo calculated after a game?

Your new rating = old rating + K × (actual score − expected score). Expected score is derived from the rating gap between you and your opponent using the logistic formula.

What is the K-factor in chess Elo?

K controls how much each game shifts your rating. Chess Global League uses K=50 for all players, which means a single decisive result can move your rating by up to 25 points.

Why do I gain more points beating a higher-rated player?

Because the system expected you to lose. The bigger the upset, the bigger the rating gain for the winner and the bigger the loss for the favourite.

Can my Elo go down even if I win?

In a single game, no — a win always increases your rating. However if you beat a much weaker player, the gain can be as small as 1–2 points, which might feel like nothing.

Ako funguje Elo rating v šachu (a prečo je dôležitý)

Elo je univerzálny jazyk šachovej sily. Keď mu porozumiete, prestanete naháňať náhodné výhry a začnete hrať múdrejšie a strategickejšie v každom kole.

Čo je Elo rating?

V roku 1960 navrhol maďarsko-americký profesor fyziky Arpad Elo matematický systém hodnotenia šachistov. Myšlienka je jednoduchá: váš rating je číslo, ktoré predpovedá, ako sa vám bude dariť proti súperovi. Ak porazíte silnejšieho, rastiete; ak prehráte so slabším, klesáte.

Dnes používa variant Elo systému každá veľká šachová organizácia — FIDE, Chess.com aj Lichess. Platí to aj v Chess Global League, kde noví hráči štartujú na 1200.

Vzorec

Po každej partii je váš nový rating:

                    Rnew = Rold + K × (S − E)
                

R_old — your rating before the game
K — the K-factor (sensitivity; Chess Global League uses K = 50)
S — your actual score: 1 for a win, 0.5 for a draw, 0 for a loss
E — the expected score, based on the rating gap between you and your opponent

Očakávané skóre (E)

Očakávané skóre je matematické jadro systému. Počíta sa logistickou (sigmoidnou) funkciou:

                    E = 1 / (1 + 10(Ropponent − Ryou) / 400)
                

A rating gap of 400 points means the stronger player has roughly a 90% expected score. A gap of 200 points gives about a 76% chance to the favourite. Equal ratings? Both players have an expected score of exactly 0.5.

Reálny príklad

Setup: You are rated 1250. Your opponent is rated 1450. K = 50.

Rating gap = 1450 − 1250 = 200 points in their favour.

Your expected score: E = 1 / (1 + 10^200/400) ≈ 0.24 (you were expected to score roughly a quarter of a point)

If you win (S = 1):
Rating change = 50 × (1 − 0.24) = +38 points → new rating: 1288

If you draw (S = 0.5):
Rating change = 50 × (0.5 − 0.24) = +13 points → new rating: 1263

If you lose (S = 0):
Rating change = 50 × (0 − 0.24) = −12 points → new rating: 1238

Notice how the system is asymmetric: beating a much stronger player earns you far more than losing to them costs. The bigger the upset, the bigger the swing.

Čo robí K-faktor

K controls the maximum rating change per game. With K = 50 (as used in Chess Global League), a single result can shift your rating by at most 25 points (a perfect upset win from exactly equal expected score). A higher K-factor makes ratings more volatile and responsive; a lower one stabilises ratings for experienced players.

FIDE uses K = 40 for new players, K = 20 for established players, and K = 10 for elite players above 2400. Chess Global League keeps it at 50 across the board to keep ratings dynamic and rewarding for all skill levels.

Rozsahy Elo ratingu — čo znamenajú čísla?

Rating Range	Level	Description
< 1000	Beginner	Learning the rules and basic tactics
1000–1199	Novice	Avoiding blunders, basic openings
1200–1399	Intermediate	Solid tactics, some positional play
1400–1599	Club Player	Consistent tactics, basic endgames
1600–1799	Advanced Club	Deep calculation, strong endgames
1800–1999	Expert	Near-tournament standard
2000+	Master	FIDE-level competitive play

Ako rýchlejšie zlepšiť svoj rating

Avoid blunders — hanging pieces lose games you should draw. Even 10 minutes of daily tactics puzzles dramatically reduces errors.
Play slightly higher-rated opponents — the Elo gain from an upset win far outweighs the cost of an expected loss.
Study endgames first — most beginner-to-intermediate games end in the endgame. Knowing King + Rook vs King alone is worth 50–100 rating points at this level.
Analyse your losses — not your wins. The mistake that cost you the game usually recurs until you consciously fix it.
Be consistent — one game a week every month compounds. Elo rewards sustained play over time.

Často kladené otázky

Čo je Elo rating v šachu?

Elo je číselné hodnotenie, ktoré odhaduje vašu silu oproti ostatným hráčom. Vyššie Elo znamená silnejšiu hru. Noví hráči v Chess Global League začínajú na 1200.

Ako sa počíta Elo po partii?

Nový rating = pôvodný rating + K × (skutočné skóre − očakávané skóre). Očakávané skóre sa počíta z ratingového rozdielu pomocou logistického vzorca.

Čo je K-faktor?

K určuje, o koľko sa rating zmení po partii. Chess Global League používa K=50, takže výrazný výsledok môže pohnúť ratingom až o 25 bodov.

Prečo získam viac bodov po výhre nad silnejším hráčom?

Pretože systém očakával vašu prehru. Čím väčšie prekvapenie, tým väčší zisk pre víťaza a väčšia strata pre favorita.

Môže mi Elo klesnúť aj keď vyhrám?

V jednej partii nie — výhra rating vždy zvýši. Proti oveľa slabšiemu súperovi však môžete získať iba 1–2 body, čo môže pôsobiť ako nič.