Describe a set of numbers or count possible outcomes, with every formula explained.
- Standard Deviation Calculator
- Combinations and Permutations Calculator (nCr, nPr)
- Descriptive Statistics Calculator (Mean, Median, Mode, Quartiles)
- Percentile Calculator
- Z-Score Calculator
- Percent Error Calculator
- Probability Calculator (Two Events)
- Odds to Probability Calculator
- Sample Size Calculator for Surveys
- Confidence Interval Calculator (Mean)
- Vote Percentage Calculator
- Batting Average Calculator
- ERA Calculator (Earned Run Average)
- WHIP Calculator (Walks + Hits per Inning)
- Stem-and-Leaf Plot Generator
- P-Value Calculator (z and t)
About these calculators
These statistics calculators summarise data and test ideas: mean, median, standard deviation, percentiles, z-scores, probabilities, combinations, sample sizes, confidence intervals and p-values, each with the formula and an example.
Every tool is free, works on phone and computer, needs no sign-up and runs in your browser: what you type is not sent to a server. Each page explains the formula, gives a worked example and answers common questions.
Some tools in this category: Standard Deviation Calculator, Combinations and Permutations Calculator (nCr, nPr), Descriptive Statistics Calculator (Mean, Median, Mode, Quartiles), Percentile Calculator, Z-Score Calculator.
Tips for accurate results
- Say whether your data is a sample or a whole population.
- Look at the median as well as the mean when values are skewed.
- A p-value is not the probability that a hypothesis is true.