Confidence Interval Calculator
Result
95% Confidence Interval[99.6323, 110.3677]
Margin of Error5.3676810636
Lower Bound99.6323189364
Upper Bound110.3676810636
Standard Error2.7386127875
↗ Math
Confidence Interval Calculator — free online calculator.
Formula
z*sigma/sqrt(n)
- Confidence Interval Calculator calculates its result from Z score, Standard deviation, Sample size. It uses the formula z*sigma/sqrt(n). Change any input to recalculate the result instantly.
- The main inputs are Sample Mean, Standard Deviation, Sample Size, Confidence Level. Enter them in the units and format shown in the calculator.
- Keep comparable quantities in compatible units whenever the formula combines or compares them.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Confidence Interval
Inputs
- Sample Mean: 105
- Standard Deviation: 15
- Sample Size: 30 n
- Confidence Level: 95%
Using Z score = 1.96, Standard deviation = 10, Sample size = 100, the calculated result is 1.96.
Sample result: Calculating…
Frequently asked questions
What does the Confidence Interval calculate?
Confidence Interval Calculator — free online calculator.
Which values should I enter?
Enter Sample Mean, Standard Deviation, Sample Size, Confidence Level using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: z*sigma/sqrt(n).
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.