Statistics & Data calculators
Statistics turns a column of numbers into a handful of figures that describe it: where the middle is, how widely the values spread, and how surprising a result would be by chance alone. Paste in your own data and these tools report the summary along with the steps behind it.
Each page explains when one measure serves better than another, such as why the median holds steady when a single outlier drags the mean, and which assumptions a test needs before its p-value means anything.
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- Average CalculatorFind the mean, median and mode of a list of numbers, along with the count, sum, minimum, maximum and range.
- Dice RollerRoll up to 100 virtual dice of any size, from d4 to d100 or custom, with modifiers, drop-lowest and drop-highest, and the odds of your total.
- Random Number GeneratorPick one or many random whole numbers or decimals from any range, with or without repeats, sorted if you like.
- Standard Deviation CalculatorSee how spread out your numbers are: sample and population standard deviation and variance, with the mean, standard error, a table and full working.
- Confidence Interval CalculatorTurn your sample results into a range of believable values for the true average or share, at 90%, 95%, 99% or any other level.
- P-Value CalculatorTurn a z, t or chi-square test statistic into a p-value, for two-tailed, left-tailed or right-tailed tests.
- Percentile CalculatorSee where a number stands in a list: find the value at any percentile, or the percentile rank of a value you have.
- Probability CalculatorKnow the chance of two things on their own? Find the chance that both, either, exactly one, or neither happens.
- Sample Size CalculatorWork out how many survey responses or measurements you need to estimate a proportion or a mean within a chosen margin of error.
- Weighted Average CalculatorFind the average when some numbers count more than others, such as grades by percentage, GPA by credits or prices by quantity, with each step shown.
- Z-Score CalculatorConvert a value to a z-score and its normal-distribution percentile, or turn a z-score back into a raw value.
- Bayes Theorem CalculatorSee how likely something really is after new evidence, such as a positive test, using Bayes' theorem, with the counts shown out of 10,000 people.
- Binomial Distribution CalculatorFind the chance of exactly, at most, or at least k successes in n separate tries, plus the average and the typical spread.
- Chi-Square Test CalculatorTest whether your counts match what you expected, or whether two things in a table are related. Get the chi-square statistic, p-value, critical value and each cell's share.
- Coefficient of Variation CalculatorFind the coefficient of variation (relative standard deviation) of a data set: the standard deviation as a percentage of the mean.
- Combination CalculatorFind how many different groups you can pick from a set when order doesn't matter. Choose r items from n, with or without repeats, as an exact whole number.
- Correlation Coefficient CalculatorSee how closely two sets of paired numbers move together with the Pearson correlation r, plus r², a t statistic and a two-sided p-value.
- Dice Probability CalculatorFind the exact chance of rolling a total, or at least or at most a total, with any number of dice of any size. Or find the chance of a face showing.
- Expected Value CalculatorFind the average result you'd get over many tries, by weighting each outcome by its chance. Also shows the variance and standard deviation.
- Five-Number Summary CalculatorFind the smallest value, first quartile, median, third quartile, largest value and interquartile range of a list of numbers.
- Frequency Table GeneratorSort raw data into groups, or count each distinct value. Get the frequencies, relative and cumulative frequencies, midpoints and the modal class.
- Geometric and Harmonic Mean CalculatorGet the right average for growth rates, ratios and speeds: the geometric and harmonic means, or the true average of percent changes.
- Linear Regression CalculatorFind the straight line that best fits your paired x and y data, with its slope, intercept, r, R² and a prediction for any x.
- Lottery Odds CalculatorSee the real odds of the jackpot and every prize tier in a pick-style lottery, with or without a bonus ball. It also shows what a ticket is worth on average.
- Margin of Error CalculatorFind how far a poll or survey percentage could be off from the sample size and confidence level, with an optional small-population correction.
- Mean Absolute Deviation CalculatorSee how spread out your numbers are: the average distance of each value from the middle, with a table showing every distance.
- Normal Distribution CalculatorFind the chance of a value falling below, above or between points on a bell curve, or the value that matches a given chance.
- Outlier CalculatorFind outliers in a data set with Tukey's fences: the lower and upper fences, the IQR, and which values fall outside.
- Permutation CalculatorCount the ways to arrange r items chosen from n, where order matters, with or without repetition, as an exact whole number.
- Poisson Distribution CalculatorFind the chance of exactly, at most, at least, fewer or more than k events, from the average count λ, with a full table.
- Standard Error CalculatorFind the standard error of the mean (how precise a sample average is) from a standard deviation and sample size, or straight from raw data.
- T-Test CalculatorCheck whether a difference between averages is real or just chance. Runs one-sample, paired and two-sample (Welch or pooled) t-tests, with the t statistic, degrees of freedom, p-value and confidence interval.