T Score Calculator
Convert a raw score to a T score (mean 50, SD 10) given the group mean and standard deviation.
About T Score Calculator
A T score rescales any normally-distributed raw score to a scale with mean 50 and standard deviation 10. It is computed by first finding the z-score, then applying T = 50 + 10z.
Formulas
Z Score
z = (x − μ) / σ
- x
- Raw score
- μ
- Mean
- σ
- Standard deviation
T Score
T = 50 + 10z
- z
- Z score
Worked example
With the default values below, T Score Calculator returns T Score of 55.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Raw Score (x)
- 75
- Group Mean (μ)
- 70
- Group Standard Deviation (σ)minimum 0
- 10
Results
- T Score
- 55.00
- Z Score
- 0.5000
Step by step
- 1Values used
- 2Z Score
- 3T Score
- 4T Score= 55.00
- 5Z Score= 0.5000
Assumptions and limits
- The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
What is the difference between Z score and T score?
A Z score has mean 0 and SD 1. A T score has mean 50 and SD 10. T scores avoid negative values, making them easier to interpret in educational and psychological testing.
What T score is considered average?
T scores between 40 and 60 are typically within one standard deviation of the mean and considered 'average'.