Statistics
Standard Error Calculator
Use the standard error calculator to estimate how much a sample mean tends to vary from sample to sample.
Standard error
—
- Square root of n
- —
Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What the standard error calculator solves
Use the standard error calculator to estimate how much a sample mean tends to vary from sample to sample.
Formula
How to use it
- Enter standard deviation.
- Enter sample size.
- Read standard error for the sample mean.
How to read the answer
Larger samples reduce standard error by the square root of sample size.
Common mistakes and edge cases
- Standard error is not the same as standard deviation.
- Sample size must be positive.
- Biased samples can still have small standard error.
Worked examples
n = 64
Standard error
1.5
Small sample
Standard error
2.5298
Frequently asked questions
What does standard error measure?+
It measures the typical sampling variation of a statistic, commonly the mean.
Why does sample size use a square root?+
Averages stabilize with sqrt(n), so quadrupling sample size roughly halves standard error.
Related calculators
Confidence Interval Calculator
Calculate confidence intervals for a mean or proportion with margin of error and z critical value.
Standard Deviation Calculator
Calculate sample or population standard deviation, variance, mean, and z-score-ready summary statistics from a data list.
Sample Size Calculator
Estimate survey sample size from confidence level, margin of error, and expected proportion.
Binomial Probability Calculator
Calculate exact binomial probability for k successes in n independent trials.
Coefficient of Variation Calculator
Calculate coefficient of variation from a data set using standard deviation divided by mean.
Correlation Coefficient Calculator
Calculate Pearson correlation coefficient r from paired x and y data.
Last updated: May 15, 2026