Chess Performance Rating Calculator
Calculate chess performance rating from your tournament score and opponents average rating, and see where it lands against the FIDE 2450 IM and 2600 GM norms.
What performance rating means
Performance rating (Rp) is your effective rating for a single tournament. It answers a simple question: if this had been your only result on record, what rating would have been consistent with this performance?
It is what FIDE uses to evaluate norms. IM and GM titles both require norm events with a performance rating above a fixed threshold, earned against a properly mixed field of rated opposition.
The two methods
The clean version, used in most online calculators and tournament reports:
Rp = Ra + dp(p)
Ra is the average rating of your opponents, p is your scoring percentage (score ÷ games), and dp is a function of percentage. The simplest form uses logit math:
dp = 400 × log₁₀(p / (1 − p))
For p = 0.5 (drew the field), dp = 0, so Rp equals your opponents’ average. Score 75% (p = 0.75) and dp ≈ +191. Score 100% and the formula breaks down, so FIDE caps it with a published lookup table.
The official FIDE method uses that Dp table, giving point differences for percentages from 1% to 99% in 1% steps. Most software approximates the table with the logit formula above; the differences are small (within 5 to 10 rating points except at the extremes).
Why norm tournaments care
A FIDE GM norm requires a 2600+ performance over at least 9 games against a properly mixed field that includes players from at least three federations and a minimum number of GMs and IMs. The performance rating is the bottleneck: you must score enough points against strong enough opponents.
Keep two different things apart here, because they are easy to confuse. CM and FM are rating titles: you need a published rating of 2200 or 2300, not a single tournament result. IM and GM are norm titles: you need qualifying performances in specific events, plus the rating.
| Title | What it takes |
|---|---|
| Candidate Master (CM) | A published rating of 2200 |
| FIDE Master (FM) | A published rating of 2300 |
| International Master (IM) | 3 norms at 2450+ performance, plus a 2400 rating |
| Grandmaster (GM) | 3 norms at 2600+ performance, plus a 2500 rating |
Reading your own number
A weekend Swiss with 5 games against an average 1700 field, where you score 4/5 (80%), gives a performance of 1941. That is 241 points above the field’s average rating, which is what the dp term measures. It is not 241 points above your own rating, and the calculator never sees your rating at all.
One swallow does not make a summer, either. Five games is a small sample, and a single strong weekend moves your published rating far less than the performance figure suggests. Real gain comes from sustained results over months.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.