Math Calculators

Fraction Calculator

Add, subtract, multiply fractions

Statistics Calculator

Mean, median, standard deviation

Sample Size Calculator

Survey sample size and margin of error

Probability Calculator

Calculate probabilities

GCF/LCM Calculator

Find GCF and LCM

Dice Probability Calculator

Exact odds that NdS plus a modifier is at least, at most or exactly a target total

Advantage and Disadvantage Calculator

d20 success chance normally, with advantage and with disadvantage, for any modifier and target

D&D Damage Per Round Calculator

Hit chance, crit chance and average damage per attack and per round against an armor class

4d6 Drop Lowest Calculator

Odds of every ability score when you roll several dice and keep the highest

Dice Pool Success Probability Calculator

Chance of enough successes in a pool of dice where each die succeeds on a target or higher

Card Draw Probability Calculator

Exact odds of drawing at least, exactly or at most k copies of a card from a deck

Poker Outs Calculator

Hold'em draw odds from your outs, the rule of 2 and 4, and the equity pot odds require

Poker Hand Odds Calculator

Probability and 1-in-N odds of every poker hand, 5-card and best five of seven

Catan Dice Probability Calculator

Cards per roll, payout chance and dry-spell odds for your settlement and city numbers

Yahtzee Odds Calculator

Best-play chance of a Yahtzee, straight, full house or kind in a turn, and which dice to keep

Party XP and Loot Split Calculator

Split XP and gold, silver and copper evenly across a party with leftovers shown

Pythagorean Calculator

Solve right triangles

Triangle Calculator (SSS, SAS, ASA, SSA)

Solve a triangle from any three sides and angles with area, heights, inradius and circumradius

Law of Cosines Calculator

Find a side from SAS or an angle from SSS with the formula shown

Arc Length Calculator

Arc length, central angle or radius from any two, with chord and sagitta

Area of a Sector Calculator

Sector and circle segment area from radius and angle or arc length

Ellipse Calculator

Area, exact perimeter, eccentricity and foci from the two axes

Regular Polygon Calculator

Area, apothem, circumradius and angles for any regular polygon

Frustum Volume Calculator

Volume and surface area of a cone or square pyramid frustum

Degrees to Radians Converter

Degrees, radians and DMS both ways, with exact fractions of pi

A/B Test Sample Size Calculator

Visitors per variant and test duration for a target lift

A/B Test Significance Calculator

z-test, p-value, relative lift and confidence interval for two conversion rates

Minimum Detectable Effect Calculator

Smallest lift an A/B test can detect with your traffic

Bayesian A/B Test Calculator

Probability that B beats A with credible intervals

Z-Score Calculator

Z-score from a value, mean and standard deviation, with percentile

P-Value Calculator

P-value from a z-score or t-score for one or two tails

Confidence Interval Calculator

Confidence interval for a mean from mean, standard deviation and size

Proportion Confidence Interval Calculator

Wilson, exact and normal intervals for a percentage or rate

Standard Error Calculator

Standard error of a mean or proportion with population correction

Scientific Notation Calculator

Convert to scientific, E and engineering notation, or add, subtract, multiply, divide and raise to a power

Significant Figures Calculator

Count significant figures and round to sig figs or decimal places, with the rule shown

Sig Fig Arithmetic Calculator

Add, subtract, multiply and divide measurements and round by the significant figure rules

Percent Error Calculator

Percent error against an accepted value, or percent difference between two values, with working

Uncertainty Propagation Calculator

Absolute, relative and percent uncertainty, and propagation through sums, products and powers in quadrature

Number to Words Converter

Spell any number in English words with ordinal forms, American or British style, up to 999 decillion

Long Division Calculator

Long division with steps, remainder and optional decimal places

Proportion Calculator

Solve a/b = c/d for the missing value with cross multiplication

Ratio Calculator

Simplify a ratio, split a total in a ratio, or scale a ratio from one amount

Percent Increase and Decrease Calculator: Reverse and Successive Changes

Percent change, a number after a percent rise or fall, and the original before it

Mixed Number to Improper Fraction Converter

Convert improper fractions to mixed numbers and back, with the steps

Simplify Fractions Calculator

Reduce a fraction to lowest terms with the greatest common factor shown

Fraction to Decimal Converter

Fractions to decimals with repeating digits, and decimals back to fractions

Unit Price Comparison Calculator

Price per unit for up to three items and which one is the best buy

Composite Shape Area and Perimeter Calculator

Area and perimeter of L-shapes, house shapes, arched shapes and shapes with a hole

Order of Operations Calculator

Evaluate an expression step by step with PEMDAS and BODMAS

Factors of a Number Calculator

All factors, factor pairs, prime or composite and the prime factorization

Quartile Calculator

Q1, Q3, IQR, five-number summary, box plot and outliers

Correlation Coefficient Calculator

Pearson r, r squared, t and p-value for paired data

Linear Regression Calculator

Least-squares line, slope, intercept, R squared and prediction

Binomial Probability Calculator

Exact, at most, at least and between-two-numbers binomial probability

Normal Distribution Calculator

Area below, above, between or outside values, plus inverse normal

Poisson Distribution Calculator

Poisson probability for exactly, at most, at least or between counts

Chi-Square Calculator

Test of independence for r x c tables, Yates for 2x2, and goodness of fit

T-Test Calculator

One-sample, Welch and pooled t-test from mean and standard deviation

ANOVA Calculator

One-way ANOVA table with F and p-value from data or mean and SD

Grouped Data Calculator

Mean, median, mode and range of a grouped frequency table

Quadratic Formula Calculator

Roots, discriminant, vertex and steps for ax² + bx + c = 0

Unit Circle Calculator

Sin, cos, tan and exact values for any angle in degrees or radians

Arithmetic Sequence Calculator

nth term, sum and common difference, from a term and difference or two terms

Geometric Sequence Calculator

nth term, sum and infinite-series convergence for a common ratio

Logarithm Calculator

Log to any base, natural log, change of base and log-law check

Matrix Calculator

2x2 and 3x3 add, multiply, determinant, inverse and transpose

Volume and Surface Area Calculator

Sphere, cone, cylinder, pyramid plus trapezoid, ellipse and sector area

Distance, Midpoint and Slope Calculator

Distance, midpoint, slope and line equation through two points

Permutation, Combination and Factorial Calculator

nPr, nCr and n! with big-integer answers and repetition counts

Confusion Matrix Calculator

Accuracy, precision, recall, specificity, F1, MCC and kappa from TP, FP, FN, TN

F1 Score Calculator

F1 and F-beta (F2, F0.5) with precision and recall from TP, FP, FN

Matthews Correlation Coefficient Calculator

MCC (phi coefficient) from a binary confusion matrix, compared with accuracy and F1

Cohen's Kappa Calculator

Cohen's kappa with optional linear or quadratic weights from an agreement matrix

Multiclass F1 Calculator (Macro, Micro, Weighted)

Per-class precision, recall, F1 with macro, micro and weighted averages from an N x N matrix

AUC ROC Calculator

Area under the ROC curve from FPR and TPR threshold points by the trapezoidal rule

Precision at K Calculator

Precision@k, recall@k, R-precision and average precision from a ranked relevance list

Positive Predictive Value Calculator (Bayes)

PPV and NPV from sensitivity, specificity and prevalence with a natural-frequency table

Train Test Split Calculator

Exact train, validation and test sample counts from percentages, with scikit-learn rounding

Training Steps and Epochs Calculator

Batches per epoch, optimizer steps, effective batch size and warmup steps for a training run

Prime Factorization Calculator

Prime factors with exponents for numbers up to 10^24, with divisor count and check

Is It Prime? Checker

Test if a number up to 10^24 is prime, with the factors if not and the next and previous prime

Modular Inverse Calculator

a^-1 mod m with the extended Euclid steps, and why no inverse exists when gcd(a, m) is not 1

Extended Euclidean Algorithm Calculator

gcd(a, b) with Bezout coefficients x and y, every division step, the LCM and a check

Birthday Paradox Calculator

Chance that two of n people share a birthday, and the group size needed for 50, 90 and 99 percent

Fibonacci Calculator

The exact nth Fibonacci number up to n = 100,000, the first terms, and a test for whether a number is Fibonacci

Collatz Conjecture Calculator

The 3x+1 sequence for any start: steps to reach 1, the peak value and the full path

Perfect and Amicable Number Checker

Classify a number as perfect, abundant or deficient from its proper divisors, and find its amicable partner

Drop Rate Calculator: Odds of At Least One Drop | TNAADO

Free drop rate calculator: the chance of at least one drop after n tries at any 1-in-N rate, and tries needed for 50%, 90%, 95% and 99%.