---
title: "Chess rating calculator: FIDE and Elo"
url: "https://georgelichess.com/tools/rating-calculator.md"
canonical_url: "https://georgelichess.com/tools/rating-calculator"
last_updated: "2026-11-05"
type: "tool"
summary: "Estimate your FIDE rating change after a set of games with the Handbook expected-score table and K factor, with the textbook Elo formula alongside."
related: ["https://georgelichess.com/tools/uscf-rating-estimator.md", "https://georgelichess.com/tools/performance-rating.md", "https://georgelichess.com/tools/time-control-calculator.md"]
---

# Chess rating calculator: FIDE and Elo

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Estimate your FIDE rating change after a set of games with the Handbook expected-score table and K factor, with the textbook Elo formula alongside.

This calculator estimates how your FIDE rating changes after a set of games. It reads the expected score for each game from the Handbook table, multiplies the gap between your points and the expected points by your K factor, and rounds to a whole number. An Elo formula view sits beside it.

## How the rating change is computed

Change = K x (points scored - sum of expected scores)

The gap between the ratings is capped at 400 points before the table is read, except for players rated 2650 or higher, who use the full gap.

When K times the number of games would pass 700, K is lowered to the largest whole number that keeps the product within 700.

## Which K applies

- K = 40: Fewer than 30 games on your rating list
- K = 40: Under 18 and rated below 2300
- K = 10: Rated 2400 or higher at any point, even if the rating later drops
- K = 20: Rated below 2400 and never above

## Worked examples

One game each, a player rated 1800 with 100 games on the list, never rated 2400.

| Game | Calculation | Expected | Exact change | Change |
| --- | --- | --- | --- | --- |
| Win against an equal rating (1800) | FIDE table | 0.50 | 10.00 | +10 |
| Win against an equal rating (1800) | Elo formula | 0.5000 | 10.000 | +10 |
| Draw against a lower rating (1700) | FIDE table | 0.64 | -2.80 | -3 |
| Draw against a lower rating (1700) | Elo formula | 0.6401 | -2.801 | -3 |
| Loss against a higher rating (2000) | FIDE table | 0.24 | -4.80 | -5 |
| Loss against a higher rating (2000) | Elo formula | 0.2403 | -4.805 | -5 |

## FIDE table or the Elo formula

The Handbook publishes a table of expected scores by rating gap, and FIDE uses that table. The textbook Elo formula, expected score = 1 / (1 + 10 ^ (-(your rating - opponent rating) / 400)), gives almost the same curve with no cap.

## Questions people ask

**Is this my official FIDE rating?** No. It estimates the change from the games you enter, using the Handbook rules, treating them as one rating period. Only the list FIDE publishes is official, and it can differ if your games fall in different periods or an event was rated in a special way.

**Why does my K factor change?** K depends on how many games you have on the list, your age and whether your rating has ever reached 2400. A higher K moves your rating faster. The tool states which rule it applied and what K it used, so you can check it against your own record.

**Will this match my online rating?** No. Online sites run their own rating systems, so their changes follow different rules. Use the Elo formula view as a textbook comparison, and keep the FIDE view for games that FIDE rates, such as over-the-board classical events.

**How many games can I enter?** Up to 20 games in one rating period. The tool uses your rating before the first game for every game in the list, which is how the Handbook treats the games of a single period. Enter games from separate periods one period at a time.

## Sources

Checked against the FIDE Handbook edition dated 1 March 2024 on 2026-10-19. Expected scores: B02 8.1.2. K factor: B02 8.3.3. Rating gap cap: B02 8.3.1.

## Related

- [US Chess (USCF) rating estimator](https://georgelichess.com/tools/uscf-rating-estimator.md)
- [Chess performance rating calculator](https://georgelichess.com/tools/performance-rating.md)
- [Chess time control calculator](https://georgelichess.com/tools/time-control-calculator.md)