Just enter the Z-score that you know and choose the type of significance test: one-tailed or two-tailed to calculate the corresponding p-value using the normal CPDF (cumulative probability density function of the normal distribution). If you obtained a Z-score statistic from a given set of data and want to convert it to its corresponding p-value (percentile), this Z to P calculator is right for you. How to interpret a low p-value (statistically significant result).Using the z-score to p-value calculator.