The pooled standard deviation calculator below gives the value of the combined standard deviation of two data sets.

**Sample 1**

**Sample 2**

**Pooled standard deviation = ** 7.739852

The pooled standard deviation refers to the combined standard deviation of two different groups of data values. Suppose that we have two data values of sizes n_{1} and n_{2} respectively.

If the standard deviations of the two data sets are S_{1} and S_{2} respectively, then the pooled standard deviation can be calculated using the formula,

S^{2} = [(n_{1}-1)S_{1}^{2}+(n_{2}-1)S_{2}^{2}]/(n_{1}+n_{2}).

The pooled standard deviation is a kind of weighted average of the standard deviations of the two given samples. The pooled variance can be calculated by taking the square of the pooled standard deviation.