Score Normalisation Calculator
Rescales a score so it can be compared with scores from another test or group.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
z = (score − average) ÷ SD standard score = target average + target SD × z min-max = new bottom + (score − lowest) ÷ (highest − lowest) × (new top − new bottom)
The percentile assumes a normal distribution, which real class marks only roughly follow.
What to watch out for
Normalising makes positions in two groups comparable. It assumes the groups are of similar ability, which is often the part that is disputed.
Frequently Asked Questions
What is a z-score?
How many standard deviations a score sits from the average. A 72 where the average is 65 and the deviation is 10 has a z-score of 0.7, roughly the 76th percentile on a normal curve.
Which method should I use?
Standard scores cope better with an odd high or low mark. Min-max is simpler and needs only the two extremes.