# What is the formula for calculating percent deviation?

Percent deviation is a phrase used in statistics and other fields of research to express how far test findings are from being correct. A calculator and a benchmark against which to measure your data are required to calculate percent deviation.

Compare your results to the norm.

You are provided a standard or theoretical outcome to expect from your data in many studies or data-recording tasks. For example, the acceleration due to gravity is 9.8 m/s2 in a physics lab that calculates the acceleration of a falling item. Your computed result may not be exactly 9.8 m/s2 due to slight inaccuracies in distance or time to fall data. Check how close your result is to the standard once you’ve completed your experiment and calculations.

Find the distinction

Subtract the smaller of the two from the larger to find the difference between your calculation and the standard. For example, if you discovered 9.5 m/s2, the difference is 9.8 m/s2 – 9.5 m/s2 = 0.3 m/s2.

Determine the percentage deviation.

The percent deviation is calculated by multiplying the difference between your data and the standard by 100 and then dividing by the standard. (|data – standard|) / 100 (standard) The following is the formula for the acceleration experiment: 100 * (9.8 – 9.5)/(9.8) = 100 * (0.3)/9.8 = 3.06 percent