Statistics, calculated clearly.
Accurate calculators and reference tables with the formulas, worked steps, and plain explanations behind every result — built for students, researchers, and analysts.
Every step shown
Not just the answer — the formula, your values substituted in, and the worked solution.
Real formulas
Each result is backed by the standard statistical formula, typeset and explained in plain English.
Free, no sign-up
Every calculator and reference table is free and unlimited. No account, no paywall, no ads in your way.
Reviewed for accuracy
Methods are checked against textbook definitions and reviewed for correctness (last: August 2026).
Calculators
21 tools across descriptive statistics, regression, hypothesis testing, and probability — each with steps and formulas.
Descriptive statistics
Summarize and describe a data set.Standard Deviation
→Sample & population standard deviation with steps.
Variance
→Population & sample variance with steps.
Percent Variance
→Variance between two numbers: percent change & difference.
Mean, Median, Mode
→The core measures of central tendency, instantly.
Coefficient of Variation
→Compute %CV from data or mean and standard deviation.
Percentile & IQR
→Quartiles, IQR, percentiles, and a box plot.
Skewness
→Measure distribution asymmetry.
Kurtosis
→Excess kurtosis (sample & population).
Correlation & regression
Model relationships between variables.Inference & hypothesis testing
Draw conclusions and test claims.P-Value
→Find p-values from a test statistic, with interpretation.
Confidence Interval
→CI for a mean using the z- or t-distribution.
Hypothesis Test
→One- and two-tailed tests with a decision.
Difference in Means
→Compare two population means.
Sample Size
→Required sample size for a survey or study.
Chi-Square
→Goodness-of-fit and independence tests.
One-Way ANOVA
→Compare the means of three or more groups.
Probability & distributions
Work with chance and the normal curve.Statistical tables
Critical values & how to read them.How it works
From raw numbers to a result you understand — in three steps.
- 1
Enter your data
Paste a column from Excel or a CSV, or type your numbers straight in. Most calculators accept commas, spaces, or new lines.
- 2
Get instant results
Results compute the moment your data changes — the mean, standard deviation, test statistic, p-value, or interval you need.
- 3
Follow the working
Expand the step-by-step solution to see the formula, the substituted values, and a plain explanation of what the result means.
Built for students, researchers & analysts
Whether you’re checking homework or a published result, the working is always in view.
Students
Check your homework and learn the method, not just the final number — perfect for exam prep and stats coursework.
Researchers
Accurate, citable results with transparent formulas and assumptions, so you can trust what goes into your paper.
Analysts & professionals
Fast, reliable calculations for everyday analysis when you need an answer — and the reasoning — in seconds.
Frequently asked questions
Are these statistics calculators free?+
Yes. Every calculator and reference table on Statistics Inference is completely free and unlimited. There is no account to create, no paywall, and no limit on how many calculations you run.
Do the calculators show step-by-step working?+
Every calculator shows the full working — the formula used, your values substituted into it, and a step-by-step solution — alongside a plain-English explanation of what the result means.
What is the difference between sample and population standard deviation?+
Population standard deviation divides by n and is used when your data covers the entire group of interest. Sample standard deviation divides by n − 1 (Bessel’s correction) and is used when your data is a sample drawn from a larger population. Our calculators report both so you can pick the right one.
Can I use these calculators for homework or research?+
Yes. The methods follow standard textbook definitions and are reviewed for accuracy, and each result exposes the formula and steps so you can verify the working and cite the method in your assignment or paper.
Do I need to install anything?+
No. Everything runs in your browser on any device — desktop, tablet, or phone. There is nothing to download or install.
How accurate are the results?+
Calculations use full floating-point precision and the standard statistical formulas, with results rounded only for display. The library of methods was last reviewed for correctness in August 2026.
Ready to run the numbers?
Pick a calculator and get an accurate answer — with every step shown — in seconds.