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Estadística · Herramienta gratuita
Desviación Estándar Relativa Calculadora
Pega un conjunto de datos o introduce SD y media conocidas — obtén RSD, varianza y resolución paso a paso en milisegundos.
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Relative Standard Deviation
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% (Coefficient of Variation) Standard Deviation (σ)—
Mean (μ)—
Variance (σ²)—
Count (n)—
Sum (Σx)—
Range—
Minimum—
Maximum—
Distribution
Step-by-step
What is RSD?
Variability, in one number.
Relative Standard Deviation — also called the coefficient of variation — expresses how spread out a data set is as a percentage of its mean. It lets you compare consistency across measurements with completely different scales: lab results, stock prices, manufacturing tolerances, exam scores.
A small RSD means values cluster tightly around the mean (high precision). A large RSD means they're scattered (high variability).
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How RSDCalc Works
From data to insight in three steps
No accounts, no setup, no friction — just paste and calculate.
Pick sample or population
Choose Sample (n − 1) for a subset drawn from a larger population, or Population (n) when your data covers everyone.
Read your results
See RSD as a percentage, plus standard deviation, mean, variance, range, and full step-by-step working.
The Math
How We Calculate RSD
Relative standard deviation expresses dispersion as a percentage of the mean — making it easy to compare variability across data sets with different scales.
Relative Standard Deviation
RSD = (σ / μ) × 100%
Divide the standard deviation (σ) by the mean (μ), then multiply by 100 to express it as a percentage.
Mean
μ = (Σxᵢ) / n
Add every value in the data set, then divide by the number of values (n) to get the average.
Sample Standard Deviation
σ = √( Σ(xᵢ − μ)² / (n − 1) )
Used when your data represents a sample of a larger population. Bessel's correction (n − 1) reduces bias.
Population Standard Deviation
σ = √( Σ(xᵢ − μ)² / n )
Used when your data represents the entire population, not a sample drawn from one.
Worked Examples
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Preguntas
Preguntas frecuentes
What is relative standard deviation (RSD)?
RSD, also called the coefficient of variation (CV), is the standard deviation expressed as a percentage of the mean. It tells you how spread out your data is relative to its average — making it easy to compare variability across data sets with very different magnitudes.
What is a "good" RSD value?
It depends entirely on context. In analytical chemistry an RSD under 2% is typically considered excellent precision; under 5% is acceptable. Financial data routinely sees RSDs of 20%+. Always compare against the expected variability for your field.
When should I use sample vs population standard deviation?
Use sample standard deviation (n − 1 in the denominator) when your data is a subset drawn from a larger group. Use population standard deviation (n in the denominator) when your data covers every member of the group you care about. Sample is the more common choice in practice.
Can RSD be negative?
RSD is conventionally reported as a positive percentage. If your mean is negative, the calculation may produce a negative number — most practitioners take the absolute value. RSD is undefined when the mean is exactly zero.
What's the difference between RSD and CV?
None — "relative standard deviation" and "coefficient of variation" are two names for the same statistic. CV is more common in finance and biology; RSD is more common in chemistry. Some authors report CV as a decimal (0.46) and RSD as a percentage (46%).
How accurate are these results?
Calculations use JavaScript's IEEE 754 double-precision floating-point math, providing approximately 15 significant digits — far more than any real measurement requires. We use the textbook formulas without shortcut approximations.