Statistics calculators & graph makers

Which tool do I need?

• Get the mean, standard deviation, and full summary of a data set — the standard deviation calculator shows every statistic and the step-by-step SD calculation.
• Summarize one data set's center and spread — the box & whisker plot maker gives the five-number summary, quartiles, and outliers.
• See how two variables relate — the scatter plot maker draws the plot with a line of best fit and its equation, R², and r.
• Measure how strongly two variables move together — the correlation coefficient calculator gives Pearson r or Spearman ρ with the working shown.
• Plan how many survey responses you need — the sample size calculator gives the minimum sample size for a target confidence level and margin of error.
• Estimate a true mean or proportion from a sample — the confidence interval calculator gives the interval (with z or t automatically) and every step.
• Convert a raw score to a z-score or percentile — the z-score calculator gives the z-score and percentile, or works as a plain z-table lookup.
• Find a percentile rank or the score at a given percentile — the percentile calculator converts between a score and its percentile on a normal distribution.
• Find a probability under a normal distribution — the bell curve generator shades a region and reads off its probability and z-score.
• Curve a set of test scores — the grade curve calculator bumps, scales, or bell-curves grades and exports the result.

Every tool runs in your browser, takes pasted data straight from a spreadsheet, and exports the chart as PNG, SVG, or PDF (and the numbers as CSV). Nothing is uploaded.