Chess Rating FAQ

• K = 40 when you are new to the rating list - until you have completed events with at least 30 rated games.
• K = 40 for all players until the end of the year of their 18th birthday, as long as their rating stays under 2300.
• K = 20 as long as your rating remains under 2400.
• K = 10 once your published rating has reached 2400 - and it stays at 10 permanently, even if you later drop below 2400.

In short: most adult club players who have played 30+ rated games sit at K = 20. New players and juniors move twice as fast with K = 40, which is why ratings converge quickly at first.

One more clause from the same article: if the number of games in a rating period multiplied by K would exceed 700, K is reduced to the largest whole number that keeps K × games at or below 700.

The FIDE method works in two steps. First take the average rating of your opponents, R_a. Then convert your percentage score p into a rating difference d_p using FIDE Table 8.1.1, and add it:

TPR = R_a + d_p

Scoring 50% gives d_p = 0, so your performance equals the field's average. A perfect 100% score gives d_p = +800 - which is really a lower bound: any 100% score against the same opponents produces the same number. An alternative convention anchors the same delta to your own rating instead: performance = your rating + d_p. A third, cruder method ("the algorithm of 400") adds 400 × (wins − losses) / games to the opponents' average.

Try the performance rating calculator →

Each game, your expected score is E = 1 / (1 + 10^{(R_opp − R_you)/400}). After the game your rating changes by ΔR = K × (S − E), where S is your actual score (1, ½ or 0) and K is your development coefficient. Beat a higher-rated player and S − E is a large positive number; lose to a lower-rated one and it bites hard in the other direction.

FIDE itself reads E from its official table (Table 8.1.2) rather than the raw curve - at a 400-point gap the table gives exactly 0.92, where the curve gives about 0.909. Both are shown side by side in our elo calculator.

For rating purposes, FIDE caps the rating difference between you and a single opponent at 400 points (Rating Regulations, art. 8.3.1). If you are rated 1500 and lose to a 2200 grandmaster, the game counts as a 400-point upset loss, not a 700-point one - you lose only what a 1900-rated opponent would lose. From 1 October 2025 the cap applies to players rated below 2650; players rated 2650 or above have their true difference counted, so elite mismatches move ratings again.

The expected score counts a draw as half a win, so E = 0.76 means "76 points per 100 games", not "76% chance of winning". The split between wins, draws and losses depends on style, opening and how drawish your level is - Elo only pins the total. Two players can both sit at E = 0.76 with completely different win/draw/loss shapes.

Compute your expected score →

It depends on K, your opponents and your scoring rate - there is no fixed number. Beating equal-rated opposition at K = 20 yields +10 per win and −10 per loss, so you need a clear net surplus of wins. The rating goal planner simulates this round by round: for example, a 1600 player on K = 20 winning every game against 1600 opponents reaches 1700 in about 11 games, because each win pays a little less as the gap grows.

A rough adult scale: below 1200 is a beginner, 1200–1600 intermediate club level, 1600–2000 strong club player, 2000–2200 expert/candidate master territory, 2200+ is FIDE master country (FM is awarded at a published 2300), 2400+ international master strength, and 2500+ is grandmaster strength. Context matters more than the number - a 1900 in a small federation's league is a serious player locally.

By the FIDE Title Regulations (art. 1.4), a GM norm requires a performance of at least 2600 and an IM norm at least 2450, over at least 9 games (with a few exceptions for elite team events), against opponents averaging at least 2380 (GM) or 2230 (IM), scoring at least 35%, with the required mix of titled opponents and federations. The title itself is awarded after norms covering at least 27 games plus a published rating of 2500 (GM) or 2400 (IM). Our performance calculator flags these benchmarks.

No. USCF (the United States Chess Federation) runs its own Elo-based system with different K-values, a 100-point floor mechanism, bonus points for fast improvers, and a rating pool that skews a few dozen to a hundred points higher than FIDE at the same objective strength in the mid-range. A 1800 USCF player is typically somewhere near 1650–1750 FIDE. The formulas on this site follow FIDE rules; the same logistic engine, different plumbing.

Because of K = 40. For your first 30 rated games every result swings 40 × (S − E) points - a win against an equal opponent is +20, not +10. FIDE also publishes new players' ratings from as few as 5 rated games in one event (initial rating = average of opponents + d_p, plus two hypothetical 1800 draws, capped at 2200). Once you pass 30 games the system deliberately slows you down.