Standard Error Calculator
Math
Estimate standard error from sample standard deviation and sample size.
Formula
SE = s / √n
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Assumes independent observations and the standard sample-mean model.
Example Calculation
Example inputs
- Sample standard deviation: 12
- Sample size: 36
s=12 and n=36 give a standard error of 2.
Frequently asked questions
How do I use this calculator?
Enter sample standard deviation, sample size. The result updates automatically. Use Reset to restore the example values.
What method does it use?
SE = s / √n. Assumes independent observations and the standard sample-mean model.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.