# Confidence Interval Calculator Calculate confidence intervals for a sample mean or proportion using either raw data or summary statistics > Canonical page: https://elysiatools.com/en/tools/confidence-interval-calculator - **Category:** Math & Numbers - **Keywords:** confidence interval, mean interval, proportion interval, statistics, margin of error, calculator ## Overview The Confidence Interval Calculator allows you to estimate the range for a population mean or proportion based on your sample data. Whether you have raw datasets or pre-calculated summary statistics, this tool provides precise margin of error and boundary calculations to support your statistical analysis. ## Inputs - **Interval Type** (select) - **Dataset (Optional)** (textarea): Enter numbers separated by commas, spaces, or new lines for a mean confidence interval - **Sample Mean (Optional)** (text): Used when dataset is empty and interval type is mean - **Standard Deviation (Optional)** (text): Used when dataset is empty and interval type is mean - **Sample Size (Optional)** (number): Used when dataset is empty and interval type is mean - **Success Count (Optional)** (text): Used when interval type is proportion - **Trial Count (Optional)** (text): Used when interval type is proportion - **Confidence Level** (select) - **Decimal Precision** (number) ## When to use - When you need to estimate a population parameter from a sample mean or proportion. - When you want to determine the margin of error for a survey or experiment result. - When you need to validate findings using specific confidence levels like 95% or 99%. ## How it works - Select the interval type: choose 'Mean' for numerical averages or 'Proportion' for percentage-based data. - Input your data: paste raw numbers directly or enter summary statistics like mean, standard deviation, and sample size. - Configure settings: select your desired confidence level and set the decimal precision for the output. - Calculate: click to generate the lower and upper bounds, margin of error, and critical value. ## Use cases - Analyzing A/B test conversion rates to determine if the results are statistically significant. - Estimating the average response time of a system based on a sample of server logs. - Calculating the reliability of survey results by determining the margin of error for a specific sample size. ## Frequently asked questions ### What is a confidence interval? It is a range of values derived from sample data that is likely to contain the true population parameter with a specified level of confidence. ### Can I use this tool with raw data? Yes, you can paste raw numbers separated by commas, spaces, or new lines into the dataset field for mean calculations. ### What confidence levels are supported? The tool supports common confidence levels including 80%, 85%, 90%, 95%, 98%, and 99%. ### How do I calculate a proportion interval? Select 'Proportion' as the interval type and enter the number of successes and the total number of trials. ### What does the margin of error represent? It represents the range above and below the sample statistic, indicating the potential deviation from the true population value. ## Related tools - [Average Calculator](https://elysiatools.com/en/tools/average-calculator): Compare arithmetic, geometric, and harmonic averages for a numeric dataset in one place - [Geometric Mean Calculator](https://elysiatools.com/en/tools/geometric-mean-calculator): Calculate the geometric mean of positive numeric values for growth rates, ratios, and multiplicative datasets - [Harmonic Mean Calculator](https://elysiatools.com/en/tools/harmonic-mean-calculator): Calculate the harmonic mean of positive values, with optional arithmetic and geometric mean comparison - [Heat Exchanger LMTD Calculator (Log Mean Temperature Difference)](https://elysiatools.com/en/tools/heat-exchanger-lmtd): Compute the Log Mean Temperature Difference (LMTD) of a heat exchanger for parallel or counter flow. 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