Chess performance rating calculator

How the performance rating is computed

FIDE turns a score into a rating by asking which rating difference matches it. Work out your score share p, round it to a whole percent, read the rating difference from the Handbook table (B02 8.1.1) and add it to the average rating of your opponents.

Rp = Ra + dp(p)

Ra is the average rating of your opponents. p is your score divided by the games played, rounded to a whole percent. dp is the rating difference the Handbook table gives for p.

Selected rating differences

Worked examples

These rows were produced by the same code as the calculator above. Enter the same totals and you will see the same numbers.

The shortcut

Many players use a quicker estimate that needs no table. It is shown beside the FIDE value and labelled as a shortcut.

Rp = Ra + 400 x (W - L) / N

W is the number of wins, L the number of losses and N the games played. A perfect score shows it: the shortcut adds +400 to the average opponent, the most it can give, while the Handbook table adds +800. The shortcut cannot pass 400 points either side of the average, and the table runs to twice that.

Sources

Checked against the FIDE Handbook edition dated 1 March 2024 on 2026-10-19. Conversion table: B02 8.1.1. FIDE Handbook.

A title norm uses this table too, but applies a rating floor and opponent-mix rules first. Use the title norm calculator for that check.

Questions people ask

How do I calculate a performance rating?

Average the ratings of the opponents you played, divide your points by the games played to get your score, and round that to a whole percent. Look the percent up in the FIDE conversion table to get a rating difference, then add it to the average. Entering your results above does all of this.

Why do the FIDE value and the shortcut differ?

The shortcut treats every extra win as the same number of rating points, so it is a straight line. The Handbook table is a curve that rises faster near the top and bottom of the score range. They sit close together in the middle and drift apart for very high or very low scores.

What if I score 100 percent or 0 percent?

The table still gives an answer, because it has a row for every whole percent from 0 to 100. It is the largest difference the table holds in either direction. A perfect result in a short event says little on its own, so read it with the number of games in mind.

Is this the same as a title norm performance?

No. A norm check starts from the same table but applies extra rules first, such as a rating floor for the lowest-rated opponents and limits on the mix of opponents. Use the title norm calculator for that. This page gives the plain performance rating for the games you enter.