Mean Confidence Margin Calculator
Calculate the margin of error for a mean from z critical value, standard deviation, and sample size.
Mean Confidence Margin measurements
Enter your values, then calculate.
Result
How to calculate mean confidence margin
Estimate the plus-or-minus margin around a sample mean when a z-based confidence interval is appropriate.
How the calculation works
Standard error is sample standard deviation divided by the square root of sample size. Multiplying by the z critical value gives margin of error.
Example
With z=1.96, standard deviation 12, and n=100, the margin of error is 2.352 units.
Frequently asked questions
How do I form the full interval?
Subtract and add the calculated margin of error to the sample mean.
Mean Confidence Margin Calculator
Standard error is sample standard deviation divided by the square root of sample size. Multiplying by the z critical value gives margin of error.
Let's understand your mean confidence margin result.
Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.
Pro Tips for Mean Confidence Margin
- Use 1.96 for a common two-sided 95% z interval.
- Use a t critical value for small samples when population standard deviation is unknown.
Common Mean Confidence Margin Mistakes to Avoid
- Using sample size instead of its square root makes the interval far too narrow.
When to Use This Calculator
Estimate the plus-or-minus margin around a sample mean when a z-based confidence interval is appropriate.