Statistics Calculators
Run hypothesis tests, build confidence intervals, check correlation, or visualize your data — free, in your browser, no account required.
Page verified • Last updated: August 2026
NumCalcX has 12 statistics calculators covering descriptive stats, hypothesis testing, regression, Bayesian inference, data visualization, and simulation. Every tool below runs entirely client-side: nothing you type is sent to a server, and there's nothing to sign up for. Click any calculator to jump straight in.
Inference & Testing
Z-Score Calculator
Enter a value, mean, and standard deviation to instantly get the z-score and percentile rank.
→Confidence Interval Calculator
Enter your sample mean, standard deviation, and sample size to get the margin of error and confidence interval bounds.
→P-Value Calculator
Enter a z or t test statistic to instantly calculate the one-tailed or two-tailed p-value.
→T-Test Calculator
Compare a sample against a hypothesized mean, or two independent samples, to get the t-statistic and p-value.
→Sample Size Calculator
Enter your confidence level, margin of error, and expected proportion to find the sample size a survey or study needs.
→Bayes' Theorem Calculator
Posterior probability P(A|B) from a prior and two conditional probabilities, with a probability tree.
→Poker Odds Calculator
Estimate starting-hand win probability against opponents using a Monte Carlo simulation.
→Data Relationships & Visualization
Correlation Coefficient Calculator
Enter paired X and Y data to instantly get Pearson's r and see a scatter plot of the relationship.
→Linear Regression Calculator
Enter paired X and Y data to get the best-fit line equation, slope, intercept, and R². Example: predicting sales from ad spend.
→Percentile Calculator
Enter a dataset to find the value at any percentile, or find the percentile rank of a specific value.
→Scatter Plot Maker
Visualize paired (x, y) data and overlay a second dataset with transparency to compare two distributions side by side.
→Histogram Maker
Visualize the distribution of your data and overlay a second dataset with transparency to compare shapes side by side.
→Frequently Asked Questions
Are these statistics calculators free to use?
Yes. Every calculator on NumCalcX runs entirely in your browser — no sign-up, no account, and no data sent to a server.
Which calculator should I use to test if two groups are different?
Start with the T-Test Calculator to get a t-statistic and p-value, then use the P-Value Calculator if you already have a test statistic from another source.
How do I check if two variables are related?
Use the Correlation Coefficient Calculator for the strength of a linear relationship, or the Linear Regression Calculator to get a predictive equation.