Z-Score Calculator
Standard score from your mark, cohort mean, and standard deviation
Your score
0.0100.0
Cohort mean
0.0100.0
Standard deviation
Must be greater than zero
Z-score
0.700
(score − mean) / SD
Interpretation
At or above mean
Compare with your institution’s grading policy
Standard score (z) for exams and coursework: how many standard deviations you are from the cohort mean. Useful for statistics and grading in education (z score calculator Sri Lanka searches often use this definition).
Measure how far your score sits from the average in units of standard deviation—common in statistics courses and standardised testing analysis.
Frequently asked questions
- What is a good z-score?
- Positive means above the cohort mean; negative means below. Magnitude shows how unusual the score is.
- Why must standard deviation be positive?
- Zero spread would mean everyone had the same mark; division by zero is undefined.
- Is this the same as grading curves?
- Institutions map z-scores to grades differently. This tool only computes the z value.