- Fraction Calculator
- Matrix Calculator
- Slope Calculator
- Algebra Calculator
- Trigonometry Calculator
- Percentage Calculator
- Probability Calculator
-
DnD Dice Roller CalculatorRoll any DnD dice combination (XdY) plus a modifier. Get your total, the dice sum, averages, and min/max possible outcomes instantly.
-
Decimal Odds CalculatorConvert decimal odds to payout, profit and implied probability. Enter your stake and the decimal odds to see your potential winnings instantly.
-
D20 Dice Roller CalculatorRoll one or more 20-sided dice (d20) online with an optional modifier. Instant random results for D&D, RPGs, and tabletop games.
-
Combination without Repetition CalculatorCalculate combinations without repetition C(n,r) = n!/(r!(n-r)!). Find how many unique groups of r items can be chosen from n, order ignored.
-
6-Sided Dice (D6) RollerRoll one or more virtual 6-sided dice (D6) with an optional modifier. See each roll, the total, min/max range, and expected average instantly.
-
Normal Approximation to the Binomial CalculatorApproximate binomial probabilities with the normal distribution using continuity correction. Enter n, p, and x to get μ, σ, z-scores and P(X).
-
D4 Dice RollerRoll one or more four-sided (D4) dice online with an optional modifier. Get the total, sum, individual rolls, and average per die instantly.
-
D10 Dice RollerRoll one or more ten-sided (D10) dice online and add a modifier. See each roll, the sum, and the grand total instantly with this free D10 roller.
-
Pearson Correlation Coefficient CalculatorCalculate the Pearson correlation coefficient (r) from paired X and Y data. Get r, r², and all sums instantly with this free statistics tool.
-
Rayleigh Distribution CalculatorCompute the Rayleigh distribution PDF, CDF, mean, variance, median and mode for any value x and scale parameter sigma. Free and instant.
-
Sampling Distribution of the Sample Proportion CalculatorFind the mean and standard error of the sampling distribution of the sample proportion using mean = p and SE = sqrt(p(1−p)/n). Free and instant.
-
Relative Frequency CalculatorCalculate relative frequency by dividing a class frequency by the total count. Get the proportion and percentage instantly with a worked example.
-
Empirical Rule CalculatorFree Empirical Rule (68-95-99.7) calculator. Enter the mean and standard deviation to find the ranges containing 68%, 95%, and 99.7% of normal data.
-
Continuity Correction CalculatorApply the ±0.5 continuity correction to approximate a binomial with the normal distribution. Computes the corrected z-score from n, p, and x instantly.
-
Chi-Square CalculatorCompute the chi-square (χ²) statistic from observed and expected values for a goodness-of-fit test. Get χ² and degrees of freedom instantly.
-
Central Limit Theorem CalculatorApply the Central Limit Theorem to find the mean and standard error of the sampling distribution from population mean μ, standard deviation σ and sample size n.
-
Elo Rating CalculatorCalculate your new Elo rating after a chess or game match. Enter ratings, result, and K-factor to find expected score and rating change instantly.
-
Roulette Payout CalculatorCalculate roulette payouts and odds for any bet. Enter your stake and numbers covered to see net profit, total return, and the true odds.
-
Lottery Odds CalculatorCalculate your odds of winning any lottery. Enter total numbers, picks, and bonus ball pool to get exact jackpot probability using combinations C(n,k).
-
Post-Test Probability CalculatorConvert pre-test probability and a likelihood ratio into post-test probability using Bayes' theorem and the odds form. Fast clinical decision tool.
-
Password Combination CalculatorCalculate the total number of possible password combinations and entropy in bits from your character set size and password length.
-
Probability of 3 Events CalculatorCalculate the probability of three independent events all occurring with P(A and B and C) = P(A)×P(B)×P(C). Also shows at-least-one and none.
-
Relative Risk CalculatorCalculate relative risk (RR) from a 2x2 table. Enter exposed/unexposed counts with and without the outcome to get the risk ratio instantly.
-
P-Hat CalculatorCalculate p-hat (sample proportion) instantly with p̂ = x / n. Enter successes and sample size to get the proportion, percentage, and complement.
