Numbers & Math

Calculators, converters and number theory.

70 tools

2D Transform Matrix Composer Compose translate / rotate / scale / skew into a single 3×3 matrix.
2D Vector Calculator Add, subtract, dot, normalize and angle-between two 2D vectors.
2×2 Matrix Calculator Determinant, inverse, product and eigenvalues of 2×2 matrices.
3D Dot / Cross Product Compute dot and cross product of two 3D vectors.
3×3 Linear System Solver Solve Ax = b for a 3×3 system using Gauss-Jordan elimination.
A/B Test Significance Two-proportion z-test for A/B test conversions.
Age in Seconds Calculator Calculate age in seconds, minutes, hours, days and years.
APR ↔ APY Converter Convert nominal annual percentage rate to effective annual yield.
Aspect Ratio Calculator Calculate proportional width or height from any aspect ratio.
AWG Wire Table American Wire Gauge diameter, area, resistance and ampacity.
Bayesian Updater Update a prior probability with sensitivity and false-positive rate.
Big Number Calculator Arbitrary-precision integer and decimal calculator: add, sub, mul, div, mod, pow, gcd, lcm, factorial.
Binomial & Poisson Calculator PMF, CDF, mean and variance for binomial and Poisson distributions.
Bitwise Calculator Calculate AND, OR, XOR, NOT and shifts with binary and hexadecimal output.
Black-Scholes Option Pricer European option pricing with Greeks.
BMI / BMR Calculator Compute Body Mass Index and basal metabolic rate (Mifflin-St Jeor).
Chi-Square Test Chi-square goodness-of-fit between observed and expected counts.
Circle Calculator Derive diameter, circumference, area from radius — plus arc, sector and chord.
Cohen's d Effect Size Standardised mean difference (small/medium/large effect).
Combinations & Permutations Calculator Compute nCr, nPr and related combinatorics values.
Complex Number Calculator Add, subtract, multiply, divide complex numbers.
Compound Interest Calculator Calculate final balance, interest earned and contributions over time.
Confidence Interval for the Mean Compute a normal-CI around the mean of a numeric sample.
Continued Fraction Expansion Expand any number into its continued fraction [a₀; a₁, a₂, …].
Cubic Equation Solver Solve ax³ + bx² + cx + d = 0 — three real or one real and two complex roots.
Decimal ↔ Fraction Convert a decimal to improper / mixed fraction and detect repeating decimals.
Equation Plotter Plot any single-variable expression in x as an inline SVG with axes and zero crossings.
Factorial / Big Integer Calculator Compute exact factorials and arbitrary-precision integer expressions.
Fibonacci Sequence Generator Generate Fibonacci numbers with index and comma-separated output.
Gamma & Beta Function Calculator Evaluate Γ(x) and B(a, b) for real arguments.
GCD / LCM Calculator Greatest common divisor and least common multiple of any list of integers.
Inflation Calculator What is $X today worth in N years at i% inflation? (and vice versa)
Line: Distance / Midpoint / Slope Given two points, get distance, midpoint, slope and line equation.
Linear Regression Ordinary least-squares slope, intercept and R² for any (x, y) list.
Loan / EMI Calculator Compute monthly payments, total interest and amortisation for a loan.
Logarithm Base Converter Convert log_a(x) into log_b(x) using change-of-base.
Mann–Whitney U Test Non-parametric two-sample rank test.
Markov Steady State Compute the steady-state probability vector of a row-stochastic matrix via power iteration.
Math Expression Evaluator Evaluate mathematical expressions with functions and constants.
Matrix Calculator Add, subtract and multiply 2x2 matrices, plus determinant values.
Modular Arithmetic Modular exponentiation, modular inverse, gcd, lcm.
Normal Distribution / Z-Score PDF, CDF, inverse CDF and Z-score for a normal distribution.
NPV / IRR Calculator Net present value and internal rate of return from a cash-flow stream.
Number Base Converter Convert between binary, octal, decimal and hexadecimal.
Numerical Integration Integrate f(x) over [a,b] with trapezoidal or Simpson's rule.
Ohm's Law Calculator Solve V, I, R, P from any two known values.
Percentage Calculator Five percentage modes: of, is what %, % change, increase, decrease.
Plane from 3 Points Find the plane equation Ax + By + Cz + D = 0 from three 3D points.
Polynomial Curve Fit Fit a polynomial to (x, y) data via least squares. Reports coefficients, R² and residuals.
Polynomial Multiplier Multiply two polynomials given by coefficient lists.
Prime Number Checker & Factorizer Check primality, factorize and list primes up to N.
PX REM EM Converter Convert CSS px, rem and em values with configurable base font size.
Pythagorean Triple Generator List primitive Pythagorean triples (a, b, c) with c ≤ N.
Quadratic Equation Solver Solve ax² + bx + c = 0 with real or complex roots.
Quaternion Calculator Quaternion arithmetic and axis-angle conversions.
Random Number Generator Generate cryptographically-random integers in a range.
Regular Polygon Calculator Interior angle, perimeter, area, apothem of a regular n-gon.
Resistor Color Code Decode resistor color bands to resistance + tolerance.
Roman Numeral Converter Convert between Roman numerals and Arabic numbers.
Salary Take-Home Calculator Estimate take-home pay after tax, social contributions and deductions.
Sample Size for a Proportion How many respondents do you need for a given margin of error?
Scientific Notation Converter Convert decimal numbers to and from scientific notation.
Simplex LP (2 variables) Maximise an objective subject to ≤ constraints — 2-variable LP via vertex enumeration.
Statistics Calculator Mean, median, mode, standard deviation and more for any list of numbers.
Tip Calculator Calculate the tip and split a bill between any number of people.
Triangle Solver Solve a triangle from SSS, SAS or ASA inputs.
Unit Converter Convert between length, mass, volume, area, speed, time and temperature.
VAT Calculator Add or remove VAT and see net, tax and gross amounts.
Welch's t-Test Compare two samples' means with Welch's unequal-variance t-test.
π / e / φ Digits Viewer View the first hundreds of digits of π, e or the golden ratio φ.