Category
Statistics
Descriptive statistics, probability distributions, regression, hypothesis tests, and sampling — all calculated locally.
Compute mean, median, standard deviation, probability distributions, regression, and hypothesis-test statistics from your data. Paste a data set or enter summary values — ideal for coursework, surveys, and quick data exploration without uploading spreadsheets.
29 tools · Private · Browser-only
Featured calculators
Popular starting points for statistics homework and quick checks.
Mean Calculator
Arithmetic average of a data set.
OpenStandard Deviation Calculator
Typical distance from the mean.
OpenZ-Score Calculator
Standardize values to the z scale.
OpenConfidence Interval Calculator
CI for a mean or proportion.
OpenLinear Regression Calculator
Best-fit line slope and intercept.
OpenProbability Calculator
Basic probability rules and complements.
OpenRecently added & popular
Guides & comparisons
Correlation vs Causation: What the Data Really Shows
Two variables moving together does not prove one causes the other. This guide explains confounders, spurious correlations, and what evidence supports causation.
Confidence Intervals Explained for Surveys and Samples
A confidence interval estimates a population parameter with a margin of uncertainty. This guide explains what '95% confident' really means.
Mean vs Median vs Mode: Which Average to Use?
The mean is the arithmetic average; the median is the middle value; the mode is the most frequent. Pick the right measure for your data shape.
Variance vs Standard Deviation: Spread Measures
Variance averages squared deviations; standard deviation is its square root, returning to original units. Both measure spread — SD is easier to interpret.
Descriptive
Mean Calculator
Arithmetic average of a data set.
OpenMedian Calculator
Middle value of sorted data.
OpenMode Calculator
Most frequently occurring value.
OpenRange Calculator
Spread from minimum to maximum.
OpenVariance Calculator
Average squared deviation from the mean.
OpenStandard Deviation Calculator
Typical distance from the mean.
OpenQuartile Calculator
Q1, Q2, and Q3 for any data set.
OpenInterquartile Range Calculator
IQR = Q3 − Q1 robust spread measure.
OpenProbability
Probability Calculator
Basic probability rules and complements.
OpenBinomial Calculator
Binomial probabilities and cumulative counts.
OpenNormal Distribution Calculator
Z-scores and normal CDF probabilities.
OpenPoisson Calculator
Rare events in fixed intervals.
OpenCombination Calculator
n choose k unordered selections.
OpenPermutation Calculator
Ordered arrangements of k from n.
OpenRegression
Hypothesis
Sampling
Other
Frequently asked questions
- Sample or population standard deviation?
- Variance and standard deviation calculators use sample statistics (n − 1 denominator) unless noted otherwise.
- Can I paste a data set?
- Yes. Descriptive tools accept comma- or space-separated values in a text area.
- Which tool for hypothesis testing?
- Use the z-score calculator for standardized values, then z-test or t-test calculators for test statistics.