This tool computes the percent deviation of a sequence of data from a standard value.

To use the calculator enter the

- sequence of values, each separated by a comma
- standard value

**Background**

**Formula**

**x _{Mean} = (1/n)*(x_{1} + x_{2} + … + x_{n})**

**D _{%} = ((x_{Mean} – x_{Std})/x_{Std})*100**

**Calculation Examples**

For a set of values 1, 5, 9 and a standard value of 7, the percent deviation can be calculated as follows:

- Find the mean value. In this case it is (1+5+9)/3 = 5.
- The percent deviation is ((5-7)/7)*100 = -28.57%

In the event that the sequence consists of only one value, say 12 then the mean value is also 12. The percent deviation is ((12-7)/7)*100 = 71.43%