📊 Relative Standard Deviation Calculator
Enter the mean and standard deviation of your data set to calculate the relative standard deviation (RSD), also known as the coefficient of variation.
What this calculator does
Relative standard deviation (RSD), also known as the coefficient of variation, expresses how much variability exists in a data set relative to its mean. It is widely used in laboratory science, quality control, and finance to compare the consistency of measurements that have different units or different scales.
How the calculation works
RSD is calculated by dividing the standard deviation by the absolute value of the mean, then multiplying by 100 to express it as a percentage: RSD = (standard deviation / |mean|) x 100. A lower RSD indicates measurements that are tightly clustered around the mean (more precise or consistent), while a higher RSD indicates greater relative spread.
Because RSD is undefined when the mean is zero, the calculator returns 0 in that case. This tool is for general scientific, quality-control, and educational use.