Statistics Calculators
A complete, free suite of statistics calculators for students, researchers, and analysts — from descriptive measures and variability to effect sizes, confidence intervals, and epidemiological risk. Each tool shows its work step by step, so you learn the method, not just the answer.
Descriptive Statistics & Variability
Summarize and measure the spread of your data — averages, deviation, and variability tools that form the foundation of any analysis.
Descriptive Statistics Calculator Popular
Mean, median, mode, SD, variance & range in one pass
Standard Deviation Calculator Popular
Population & sample SD with full working
Pooled Standard Deviation Calculator
Combine SD across two or more groups
Relative Standard Deviation Calculator
RSD as a percentage for lab & QC work
Coefficient of Variation Calculator
Compare variability across different scales
Weighted Standard Deviation Calculator
SD when values carry different weights
Variance Calculator
Population & sample variance, step by step
Trimmed Mean Calculator
Robust mean that drops extreme values
Winsorized Mean Calculator
Robust mean that caps outliers instead
Distribution Shape & Position
Understand where values sit and how your distribution is shaped — quartiles, spread, symmetry, and tail behavior.
Quartile Calculator with Steps
Q1, Q2, Q3 with the full method shown
Interquartile Range Calculator
IQR & outlier fences from your data
Percentile Calculator
Find any percentile or a value’s rank
Skewness Calculator
Measure asymmetry in your distribution
Kurtosis Calculator
Gauge tail heaviness & peakedness
Z-Score Calculator
Standardize values & find probabilities
Inference, Confidence & Sampling
Move from sample to conclusion — estimate error, size your study, build confidence intervals, and test significance.
Standard Error Calculator
SE of the mean from SD and sample size
Margin of Error Calculator
Precision of a survey estimate
Confidence Interval Calculator Popular
CI for a mean or proportion
Sample Size Calculator Popular
How many respondents you actually need
P-Value Calculator Popular
From Z, t, chi-square, F or r
T-Test Calculator
One-sample, paired & two-sample t-tests
Chi-Square Test Calculator
Independence & goodness-of-fit tests
Fisher Exact Test Calculator
Exact 2×2 test for small samples
Effect Size, Association & Risk
Quantify how big a difference is and how strongly things relate — effect sizes, correlation, and epidemiological risk measures.
Cohen’s d Calculator
Standardized mean-difference effect size
Hedges’ g Calculator
Bias-corrected effect size for small n
Cramer’s V Calculator
Association strength for categorical data
Correlation Coefficient Calculator
Pearson’s r between two variables
Odds Ratio Calculator
OR with confidence interval for 2×2 data
Relative Risk Calculator
Risk ratio with confidence interval
Step-by-step working
Every calculator shows the formula and each calculation stage, so you can check your work and actually learn the method.
Instant & interactive
Paste your data and results update live — no calculate button, no reloads, with clear visual output on every tool.
Free on any device
Every tool is completely free, needs no signup, and works on phones, tablets, and desktops for coursework or research.
The Complete Statistics Calculator Collection
Statistics moves in a logical order — you describe your data, understand its shape, draw inferences about the wider population, and then measure how large and meaningful your findings really are. This hub is organized to follow exactly that workflow, grouping every tool into four stages so you can find the right calculator by where you are in your analysis rather than by hunting through an alphabetical list.
Start with Descriptive Statistics & Variability to summarize your dataset and measure its spread. Move to Distribution Shape & Position to locate values and assess symmetry and outliers. Use Inference, Confidence & Sampling to size a study, estimate error, and test hypotheses. Finish with Effect Size, Association & Risk to report how big and how strong your results are — the measures journals increasingly require alongside p-values.
Which calculator should you use?
| Your question | Recommended tool | Category |
|---|---|---|
| How spread out is my data? | Standard Deviation Calculator | Descriptive |
| Is my data skewed or has heavy tails? | Skewness & Kurtosis | Shape |
| How many people do I need to survey? | Sample Size Calculator | Inference |
| Is my result statistically significant? | P-Value Calculator | Inference |
| How big is the difference between groups? | Cohen’s d Calculator | Effect Size |
| How much more likely is an outcome? | Relative Risk Calculator | Risk |
Built for students and researchers alike
Whether you’re checking homework, preparing a dissertation, or running analysis for a paper, these tools are designed to be both a shortcut and a teacher. The step-by-step output means you can verify a hand calculation, see precisely where a textbook formula applies, and produce results you can confidently cite. For effect sizes and risk measures, the calculators also return confidence intervals where appropriate — the detail reviewers expect in modern reporting.
Frequently Asked Questions
Yes. Every calculator in this hub is completely free, with no signup, no email required, and no usage limits. You can run unlimited calculations, view the step-by-step working, and use them for coursework, research, or professional analysis at no cost.
Yes — that’s a core design goal. Each tool displays the relevant formula and walks through the calculation stages so you can follow the logic, check a manual computation, and learn the underlying method. This makes them useful for studying, not just for getting a quick number.
Both measure the standardized difference between two group means. Cohen’s d uses the pooled standard deviation, while Hedges’ g applies a correction factor that reduces bias when sample sizes are small (roughly under 20 per group). For small studies, Hedges’ g is generally the more accurate choice; for larger samples the two converge.
Relative risk (risk ratio) is most appropriate for cohort studies and randomized trials where you can measure incidence directly, and it’s easier to interpret. Odds ratios are used in case-control studies where incidence can’t be measured, and they approximate relative risk when the outcome is rare. Both are provided with confidence intervals in our calculators.
Use the P-Value Calculator to convert a test statistic (Z, t, chi-square, F, or r) into a p-value, or use the dedicated T-Test, Chi-Square, or Fisher Exact Test calculators to run the full test from your data. A p-value at or below your chosen threshold (commonly 0.05) indicates statistical significance — but pair it with an effect size for a complete picture.
Yes. This hub is actively expanding with tools like ANOVA, regression, and additional non-parametric tests based on what students and researchers search for most. Bookmark this page and check back, or explore the full DexoCalc directory for calculators in other categories.
Looking for more than statistics tools?
DexoCalc is a free directory of interactive calculators across finance, health, travel, everyday life, and more. Head back to the homepage to explore every category.