FIDE Rating Calculator
Enter both ratings, pick the result, and see what the game is worth — using FIDE’s own Elo formula, K-factors and 400-point rule.
Knowing the maths is the easy part
Gaining them is the hard part. Sit in on a free class with a FIDE-certified coach — they will find what is costing you points, and what to fix first.
FIDE rating questions, answered
FIDE uses the Elo formula. It works out your expected score — E = 1 / (1 + 10 ^ ((their rating − yours) / 400)) — then multiplies the gap between what you scored and what was expected by your K-factor: ΔR = K × (S − E).
A 1600 beating an 1800 at K = 20 gains 20 × (1 − 0.24) = 15 points. Score exactly what your rating predicts and you gain nothing.
It limits how much one game can move your rating. FIDE uses 40 for new players until 30 rated games, 40 for under-18s rated below 2300, 20 for established players below 2400, and 10 for anyone who has ever reached 2400.
You do not choose it — it follows from your age, experience and peak rating. The K = 10 band is permanent once entered.
The bigger the gap, the bigger the reward. At K = 20, beating someone 100 points above you is worth 13, 200 above is worth 15, and 400 or more is worth 18.
The reverse is just as true: losing to someone 200 below costs 15. Ratings fall through avoidable losses faster than they climb through expected wins.
When two players are more than 400 points apart, FIDE treats the gap as exactly 400. That caps both reward and risk: a 2200 beating a 1500 gains the same as against an 1800.
Without it, the favourite would gain almost nothing for a win and lose a great deal for a defeat — so strong players would avoid these games.
Get a FIDE ID from your national federation, then play FIDE-rated tournaments. After at least five games against rated opponents and a score of at least half a point, your first rating appears on the next monthly list.
Those games can span several events. A zero score against rated opponents produces no rating at all.
FIDE publishes ratings down to a floor of 1400. A player below that stays on the list at the floor rather than dropping further.
The floor has moved over the years, so older articles quoting 1000 or 1200 are out of date.
A new rating list is published on the first of every month. A tournament finishing mid-month normally lands on the following list, once the organiser has reported it.
Between lists your official rating does not change, however many games you play. This calculator shows what the next one will say.
No. Each site runs its own pool with its own starting values and maths, so the numbers are not interchangeable and there is no official conversion.
Online blitz and bullet ratings usually sit well above a player’s FIDE classical rating. Only FIDE-rated over-the-board games affect your FIDE rating.
Yes. Any result below your expected score reduces it, including a draw against a lower-rated opponent. A peak rating is not protected — only the K = 10 band and the 1400 floor are permanent.
So consistency beats one good tournament: a strong event can be undone by a weak one, and steady play against slightly stronger opposition is the reliable way up.
Turn the calculation into a climb
Our students train with Grandmasters and International Masters — and their rating graphs show it. Book a free class and find out what is holding yours back.
Calculate Your Chess Rating with FIDE Rating Calculator
A FIDE chess rating is updated based on a player's results against rated opponents, the opponents' ratings, and the player's K-factor. The calculation compares the score a player actually achieves with their expected score. Scoring better than expected generally increases a rating, while scoring below expectations generally decreases it.
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1. The Expected Score Formula
The Elo formula provides an approximation of the expected score based on the rating difference between two players:
Expected Score (E)
E = 1 / (1 + 10^((Opponent Rating − Your Rating) / 400))
A higher-rated player is expected to score more against a lower-rated opponent, while a lower-rated player has a smaller expected score. The expected score is not a guaranteed win probability; it represents the expected number of points scored per game.
Note: FIDE's official rating calculations use published rating-difference tables. The formula above is a mathematical approximation of those tables.
2. The Rating Change Formula
The estimated rating change for an individual game can be expressed as:
Rating Change (ΔR)
ΔR = K × (S − E)
Where:
K-factor (K): Determines how strongly a result affects the rating.
Actual Score (S): 1 for a win, 0.5 for a draw, and 0 for a loss.
Expected Score (E): The expected score based on the rating difference.
For official FIDE calculations, the rating differences for all applicable games in a rating period are combined, multiplied by the applicable K-factor, and rounded according to FIDE regulations.
3. Example: Calculating a Chess Rating Change
Suppose you have a rating of 1600 and play against an opponent rated 1800. Your K-factor is 20.
Step 1: Calculate the expected score
E = 1 / (1 + 10^((1800 − 1600) / 400))
E ≈ 0.24
Step 2: Estimate the rating change for each possible result
Game result | Calculation | Estimated change |
|---|---|---|
Win | 20 × (1 − 0.24) | +15 points |
Draw | 20 × (0.5 − 0.24) | +5 points |
Loss | 20 × (0 − 0.24) | −5 points |
4. What Is the K-Factor in Chess?
The K-factor controls how responsive a player's rating is to results. Under FIDE's standard rating regulations, the main K-factor rules are:
K = 40: For a player new to the rating list until they have completed events with at least 30 games, and for eligible players under 18 whose rating remains below 2300.
K = 20: For players whose rating remains below 2400, subject to the other applicable rules.
K = 10: Once a player's published rating reaches 2400, this K-factor remains applicable even if their rating later falls below 2400.
Additional rules can affect the applicable K-factor, including a cap based on the number of games in a rating period. Check the official FIDE Rating Regulations for the complete rules.
5. What Is FIDE's 400-Point Rule?
FIDE limits the rating difference used in expected-score calculations in specified circumstances. Under the standard rating regulations effective from 1 October 2025, differences above 400 points are treated as 400 for players rated below 2650. For players rated 2650 or higher, the actual difference is used.
Rapid and blitz ratings have separate regulations, including their own 400-point rule. The applicable rules therefore depend on the rating category.
Calculate Your Estimated FIDE Rating Change
Use the Kingdom of Chess's FIDE Rating Calculator to enter your rating, your opponent's rating, the game result, and the applicable K-factor. The calculator can help you understand the estimated effect of a result on your rating.
Remember that a calculator estimate is not an official rating update. FIDE processes eligible rated games under its regulations and publishes official ratings through its rating lists.
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