Standard Deviation (SD) Calculator from Reference Range

Determine the Standard Deviation and Mean from the low and high limits of the acceptable or reference ranges.

SD Range = number of standard deviations represented by the manufacturer’s reference limits (e.g., ±2 SD or ±3 SD).

Please click here if you would like to calculate the standard deviation using a given set of data points.

Formula:

Mean = (Low Limit + High Limit) /2
Standard Deviation = (Mean – Low Limit) / 2
**For example, if your reference range is 200-400 mg/dl, then your lower limit is 200 and your high limit is 400**

Principle:

Mean is simply the average between the low and high limit of the acceptable range. To achieve a confidence limit of 95%, the low and high limits of the reference range is calculated using +/- 2SD. Hence, SD is equals to half of the difference between the mean and the low limit or high limit.

Please check out our list of calculators for Laboratory Statistics:

• Standard Deviation Calculator from Reference Range
• Standard Deviation Calculator using Data Points
• Calibration Verification and Linearity
• Method Validation and Correlation