# P-Value Calculator

You can use this p-value calculator to calculate the right-tailed, left-tailed, or two-tailed p-values for a given z-score. It also generates a normal curve and shades in the area that represents the p-value.

To use the calculator, simply input the z-score for the standard normal distribution, select the p-value type, and then click on the "Calculate" button to generate the results.

## What is the formula to calculate p-value?

It is very difficult to calculate p-value manually. The most commonly employed way of doing this is to utilize a z-score table. In a z-table, the zone under the probability density function is presented for each value of the z-score.

It is also possible to employ an integral to determine the area under the curve. The standard normal distribution function that is used to do this is as follows:

Ï†(z) = (1 / âˆš2*Ï€*) Ã— *e *^{-z2/2}

Where: âˆ’âˆž < **z** < âˆž, ** e** is the base of the natural logarithm (2.718282),

**is the constant (3.1415926).**

*Ï€*