About the Elo Rating Calculator
This Elo rating calculator works out how many points each player gains or loses after a single game. Enter your rating, your opponent’s rating, the result (win, draw or loss) and the K-factor, and it shows the expected score for both sides, the rating change and the new ratings. A table also shows what a win, a draw and a loss would each do, so you can see what is at stake before you sit down.
It is useful for chess players checking a FIDE, national-federation or club rating, for online players curious how rating systems react to upsets, and for anyone running an Elo ladder for table tennis, video games, pool or office foosball. The same maths powers many sports power rankings.
The calculator uses the classic logistic Elo formula. FIDE uses a lookup table based on the normal distribution that gives almost the same expected scores, and it treats rating gaps over 400 points as exactly 400 for players rated below 2650 — tick the option to apply that cap. Official ratings are calculated over a whole rating period, so small rounding differences against your federation’s published figure are normal.
With the default inputs, the your new rating is 1,607.2. Change any value above to recalculate instantly.
How to use the elo rating calculator
- 1Enter your current rating and your opponent’s rating.
- 2Pick the result of the game from your point of view.
- 3Set each player’s K-factor (FIDE uses 40, 20 or 10; many clubs and sites use 16–32).
- 4Tick the 400-point cap if you want to follow FIDE rules for big rating gaps.
- 5Read your new rating, then check the table to compare a win, draw and loss.
Formula and method
The expected score E is the share of points a player should average against this opponent. A 400-point advantage makes you a 10-to-1 favourite (E ≈ 0.909); equal ratings give E = 0.5. After the game, the rating moves by K times the difference between the actual score S (1 for a win, 0.5 for a draw, 0 for a loss) and the expected score.
Because the two expected scores add up to 1, a game between players with the same K-factor is zero-sum: whatever one gains, the other loses. Different K-factors (for example a new player on K = 40 against an established player on K = 20) make the changes unequal. FIDE computes E from a normal-distribution table rather than this logistic curve, which agrees to within about a percentage point for typical gaps.
- R_A, R_B
- Ratings before the game
- E_A
- Expected score for player A (0 to 1)
- S_A
- Actual score: 1 win, 0.5 draw, 0 loss
- K
- K-factor — the maximum points that can change hands in one game
Worked examples
1600 beats a 1500 player, K = 20
A 100-point advantage gives an expected score of 1 ÷ (1 + 10^(−0.25)) = 0.640. Winning scores 1, so the change is 20 × (1 − 0.640) = +7.2 and the new rating is 1607.2. The opponent loses the same 7.2 points.
Upset: 1400 junior (K = 40) draws a 1800 player (K = 20)
With a 400-point gap the junior’s expected score is 1 ÷ (1 + 10) = 0.091. A draw is worth 0.5, so the junior gains 40 × (0.5 − 0.091) = +16.4 points while the 1800 player, on K = 20, loses 20 × (0.5 − 0.909) = −8.2.
Big gap with the FIDE 400-point cap
The real gap is 500 points, but with the cap it counts as 400, so the favourite’s expected score is 0.909 instead of 0.947. A win therefore earns 20 × (1 − 0.909) = +1.8 points rather than about +1.1.
Frequently asked questions
How is Elo rating calculated?+
Each game, your rating changes by K × (actual score − expected score). The expected score comes from the rating gap: 1 ÷ (1 + 10^(gap ÷ 400)). Beat a stronger player and you gain more; lose to a weaker one and you drop more.
What K-factor does FIDE use?+
Under the FIDE Rating Regulations, K = 40 for new players until 30 games and for juniors under 18 rated below 2300, K = 20 while a rating is under 2400, and K = 10 once a player has reached 2400. Many online sites use their own systems such as Glicko-2.
How many points do I get for beating someone 200 points higher?+
Your expected score against a player 200 points higher is about 0.24, so a win earns K × 0.76 — about 15 points with K = 20, or 30 points with K = 40. A draw would earn about 5 points with K = 20.
What does a 400-point rating difference mean?+
A 400-point gap means the stronger player is expected to score about 91% of the points, roughly 10 wins for every loss. Under FIDE rules any gap above 400 is treated as 400 for players rated below 2650.
Is chess.com or Lichess rating Elo?+
Not exactly. Chess.com and Lichess use Glicko or Glicko-2, which add a rating deviation that makes new or inactive accounts move faster. The Elo formula here still gives a good estimate of how a single game shifts a rating.
Why does my official rating differ slightly from this result?+
Federations total the expected scores for all games in a rating period and round only at the end, FIDE uses a normal-distribution table instead of the logistic formula, and special rules apply to new players. Expect differences of a point or less per game.