FIDE Standard Chess Rating Change Calculator uses only the stated values, rules, or dated dataset supported by this calculator's method. The result is a planning comparison and does not guarantee a price, trade, score, or outcome.
This formula passed its registered engineering tests and is published under an explicit site-owner policy authorization. No independent expert, QA, editorial, legal, or third-party review is claimed. Verify consequential results with a qualified professional.
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FIDE rating worksheet
Audit your rating period
Add each rated game as one row, choose the result, and review the projected change game by game.
Game by gameFIDE table
Rating scorecard
Projected period result
v1.0.0
Projected rating
0Projected rating changeNo rating change
1,600→1,600Entered rating to projected rating
Score check
Actual vs expected
0
Actual score0.5
Expected score0.5
Applied K
20
Rated games
1
Average opponent
1,600
K reduced?
No
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Current FIDE rules applied
FIDE rule effective 1 October 2025: each rating difference is capped at 400
Move list
Game-by-game FIDE rating audit
Entered results and formula-produced rating effects
Rd
Opponent
Result
Expected
Δ rating
1
1,600
Draw
0.5
0
FIDE rating guide
How FIDE standard rating changes work
A FIDE rating does not move by a fixed amount for every win, draw, or loss. It moves according to how your actual score compares with the score FIDE expected from each rating difference. Beating a stronger player is worth more than beating a weaker one; losing to a stronger player costs less than losing to a weaker one.
Expected score
FIDE table 8.1.2
Game score
Win 1 · Draw ½ · Loss 0
Rounding
Once, after the period total
The calculation
Actual score minus expected score
For every rated game, subtract the expected score (PD) from the actual score (S). Add those differences for the entire rating period, multiply the total by the applied K-factor, and round the period result to the nearest whole point. When the unrounded value is exactly halfway between two integers, FIDE rule 8.3.4 rounds 0.5 away from zero, so +4.5 becomes +5 and −4.5 becomes −5.
ΔR = round(Kapplied × Σ(Si − PDi))
S
The result in one game: 1, ½, or 0.
PD
Your scoring probability from FIDE table 8.1.2.
K
The development factor that scales the period change.
A positive total means you scored above expectation and gain rating. A negative total means you scored below expectation and lose rating. This is why a draw can gain points against a stronger opponent or lose points against a weaker one.
Expected score
FIDE uses a published lookup table
Table 8.1.2 converts the absolute rating difference into two complementary scoring probabilities. Equal ratings produce 0.50 for each player. A 200-point difference falls in the 198–206 band, so the higher-rated player receives 0.76 and the lower-rated player receives 0.24.
Selected bands from FIDE table 8.1.2
Rating difference
Higher-rated PD
Lower-rated PD
0–3
0.50
0.50
92–98
0.63
0.37
198–206
0.76
0.24
392–411
0.92
0.08
Worked example
Two games, calculated from start to finish
Suppose K = 20 applies to a 1600-rated player and these are the only rated games in the period. They draw an 1800-rated opponent, then beat a 1400-rated opponent. Both games have a 200-point rating difference.
The +5.2 and +4.8 game contributions are not rounded separately. They are summed first, and only the complete rating-period change is rounded. The same method works for losses and for periods with more games.
For supporting checks, the Statistics Calculator can summarize a longer opponent-rating list, the Percentage Calculator can express the projected move relative to the starting rating, and the Rounding Calculator can illustrate ordinary rounding cases. None of those substitutes for FIDE's table lookup or its rule to round the complete period change once.
K-factor
Choose the K that applies to your official history
K determines how strongly a result moves the rating. A larger K reacts faster; a smaller K makes each game less influential. The correct value depends on more than the rating visible today, so this calculator asks you to enter K instead of guessing it.
K = 40
New or eligible junior player
A player new to the rating list uses K = 40 until they have completed rated events totaling at least 30 games. K = 40 also applies through the end of the year of a player’s 18th birthday while their rating remains below 2300.
K = 20
Published rating below 2400
K = 20 normally applies while the published rating remains below 2400, unless the new-player or junior K = 40 rule applies.
K = 10
Reached a published 2400
Once a player has reached a published rating of 2400, K = 10 continues to apply even if that rating later falls below 2400.
Current regulation
The 400-point rule changed on 1 October 2025
When the entered player is rated below 2650, a rating difference greater than 400 is treated as 400 when the calculator looks upPD. For a player rated 2650 or above, the full rating difference is used. This rule is applied from the entered player's perspective for every game.
Player below 2650D = min(|Rplayer − Ropponent|, 400)
Player at least 2650D = |Rplayer − Ropponent|
Scope
Use the correct FIDE standard list and rated games
This calculator covers
An already rated player's ordinary rating-period change
Rated opponents entered in the same order as the results
The relevant current FIDE standard rating list
A projected new rating based on the information entered
It does not calculate
An unrated player's first FIDE rating
FIDE rapid or blitz rating periods
Title norms, performance ratings, or game eligibility
Federation submissions, corrections, or publication timing
Chess.com, Lichess, US Chess, or another rating pool
Standard, rapid, and blitz ratings are separate pools with separate regulations. This version is limited to standard chess because the rapid and blitz rules handle large rating differences differently. Do not mix time controls or online-platform ratings into the period. Unrated opponents and initial-rating assignment follow separate FIDE procedures and are outside this tool.
Questions
Common points of confusion
Can I gain rating from a draw?
Yes. If your expected score against a stronger opponent is below 0.50, a draw is better than expectation and produces a positive contribution. A draw against a weaker opponent can do the opposite.
Why does the published rating sometimes differ?
This is a projection from the data entered. The official list can differ because of excluded or corrected games, rating-list timing, federation processing, an incorrect K-factor, or later rule changes.
Can I convert a Chess.com or Lichess rating to FIDE?
No exact conversion exists. Each platform has its own player pool, update method, and time-control definitions. Use this calculator only with published FIDE ratings.