Statistics calculator
Standard Error Calculator
Calculate standard error and an approximate 95% margin from standard deviation and sample size.
Formula
Standard error
The 95% margin uses a normal approximation and is not a substitute for full study design.
SE = standard deviation / sqrt(sample size)
SD 12 and n 64 gives standard error 1.5.
FAQs
What is standard error?+
It estimates how much a sample mean varies from sample to sample.
How does sample size affect it?+
Larger sample size reduces standard error by the square-root relationship.
How does the Standard Error Calculator calculate the result?+
It uses the Standard error: SE = standard deviation / sqrt(sample size). SD 12 and n 64 gives standard error 1.5.
What information do I need to use the Standard Error Calculator?+
Calculate standard error and an approximate 95% margin from standard deviation and sample size.
How accurate is the Standard Error Calculator?+
Standard Error Calculator applies the formula and assumptions shown on this page. Results may be rounded for readability, so verify changing rates, thresholds, medical guidance, or legal rules with the cited source or a qualified professional.
What should I check before using the Standard Error Calculator result?+
Check that the units, dates, rates, and assumptions match your situation. Change one input at a time to understand which values have the largest effect on the result.
Statistics guide
How to use the Standard Error Calculator
Calculate standard error and an approximate 95% margin from standard deviation and sample size. The page also explains the standard error and shows a practical example: SD 12 and n 64 gives standard error 1.5.
- 1
Enter your details
Enter standard deviation and sample size, then complete any other fields shown in the calculator.
- 2
Check the calculation
Review the result alongside the standard error: SE = standard deviation / sqrt(sample size).
- 3
Compare scenarios
Change one or more inputs to see how they affect the standard Error Calculator result before you use the estimate.
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