Confidence Interval Calculator
Statistically calculate confidence intervals for means and proportions. Specify sample size and confidence level to perform interval estimation.
How to Use
Enter Data
Enter sample size, mean, and standard deviation (or proportion)
Select Confidence Level
Select confidence level (90%, 95%, 99%, etc.)
Check Results
Check upper limit, lower limit, and margin of error
Features
Mean & Proportion
Calculate confidence intervals for both population mean and proportion
t-Distribution Support
Use t-distribution for accurate confidence intervals with small samples
Required Sample Size
Reverse-calculate the required sample size for a target margin of error
FAQ
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