This calculator determines the Zscore cut off value from the population mean, standard deviation, and percentile.
The Zscore cut off value can be calculated using the following steps:
First, find the Zscore value corresponding to the x^{th} percentile using the Zscore Table or Percentile to Zscore Calculator.
For example:
Percentile  Zscore 

90^{th}  1.28155 
95^{th}  1.64485 
99^{th}  2.32635 
Now use the Zscore formula:
Z = 

X = (Z × σ) + μ
Where,
X = Cutoff value,
Z = Zscore for the x^{th} percentile,
μ = Mean,
σ = Standard deviation.
Let's take an example.
Suppose, the mean is 82 and the standard deviation is 12. Calculate the Zscore cutoff value for the 99^{th} percentile.
Here,
Mean (μ) = 82,
Standard deviation (σ) = 12,
Percentile = 99^{th}.
1. Find the Zscore for the 99^{th} percentile.
Z = 2.32635
2. Put all the values in the formula.
X = (Z × σ) + μ
X = (2.32635 × 12) + 82
X = 27.9162 + 82
X = 109.916