Free tool
Performance rating calculator
How it works
Enter the rating of every opponent you faced and your total score. The linear performance rating is the average opposition rating plus 800 times your score percentage minus 400, so a 50% score performs exactly at the average of the field.
Average opposition
1490
Score percentage
75%
Performance rating
1690
Linear method: average + 800 x score% - 400
This is the linear approximation used for quick tournament estimates. FIDE's official norm calculations use a percentage-to-rating-difference table that differs at extreme scores (near 0% or 100%), where the linear method understates the swing.
The method behind the numbers
Rp = average opposition + 800 x (score / games) - 400
Performance rating answers a different question than your rating change: not "what is my new rating" but "what rating did I play like this event". A 75% score against 1500-average opposition is a roughly 1700 performance regardless of what your own rating was coming in.
The linear formula is the standard quick method. FIDE’s official norm calculations instead convert your percentage to a rating difference using a lookup table, which matches the linear method closely in the middle of the range and diverges at extreme scores: a 100% score is technically an infinite performance, which the table caps.
Coaches use performance rating to spot signal inside one event: a student whose performance beats their rating by 150+ points in consecutive tournaments is usually underrated and about to climb.
Frequently asked questions
What does a performance rating actually mean?
It is the rating that would make your score exactly expected. If you scored 6/9 against 1600-average opposition, your performance is about 1733: a 1733-rated player would be expected to score 67% against that field. It measures one event, not your overall strength.
Why is my performance rating infinite when I score 100%?
Because no finite rating makes a perfect score exactly expected; the formula divides by zero conceptually. The linear method returns average + 400 for a perfect score, while FIDE caps the conversion at 800 points above the average opposition. Both are conventions, not measurements.
Is performance rating used for FIDE norms?
Yes, title norms require a minimum performance rating across a qualifying event, calculated with FIDE’s conversion table rather than the linear formula, along with requirements on opposition mix. Check the FIDE Handbook for current norm regulations before planning a norm hunt.
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