Pick your Calculation Type (population or sample), enter your Chemical Data Values, and this Standard Deviation Calculator will crunch the spread in your lab results — giving you the Standard Deviation alongside the Variance, Mean, Number of Values, and Sum of Squares.
Standard Deviation
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Variance
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Mean (Average)
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Number of Values
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Sum of Squares
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Relative Standard Deviation (RSD)
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Sample standard deviation (n-1) is used when analyzing a subset of data from a larger population, like lab measurements. Population standard deviation (n) is used when you have the complete dataset. For most chemistry lab work, use sample standard deviation.
A low standard deviation indicates precise measurements with little variation, while a high standard deviation suggests greater experimental error or natural variation. In analytical chemistry, lower values typically indicate better measurement precision.
RSD is the standard deviation expressed as a percentage of the mean. It's useful for comparing precision across different measurement scales and is commonly used in analytical chemistry to express measurement uncertainty.
Yes, you can enter data separated by commas, spaces, or line breaks. The calculator accepts decimal numbers and can process data copied from Excel spreadsheets or laboratory notebooks.
Variance is the square of standard deviation and represents the average squared deviation from the mean. While less intuitive than standard deviation, it's important in statistical calculations and represents the spread of your data.
For meaningful statistical analysis, you typically need at least 3-5 data points, though more measurements (10+) provide better reliability. In analytical chemistry, triplicate measurements are common practice.
Sum of squares is the sum of all squared deviations from the mean. It's calculated by taking each data point, subtracting the mean, squaring the result, and adding all these squared values together.