Mathematical concepts, functions, and applied math calculators. Browse our free general math tools below — all calculators are instant, accurate, and require no sign-up.
Galileo's Paradox of Infinity Explorer — Explore Galileo's paradox interactively — compare counting numbers with perfect squares, visualize bijections, and understand infinite set cardinality.
Hilbert's Hotel Paradox Simulator — Simulate Hilbert's Hotel thought experiment — accommodate new guests in a fully-occupied infinite hotel and explore cardinal arithmetic interactively.
Complex Number (i) Calculator — Perform complex number arithmetic — add, subtract, multiply, divide, raise to powers via De Moivre, find modulus, argument, polar form, and conjugate.
Luhn Algorithm Calculator — Validate credit card numbers, IMEI codes, and other IDs using the Luhn checksum algorithm. Generate check digits with step-by-step visualization.
Mayan Numeral Calculator — Convert between decimal and Mayan vigesimal (base-20) numeral system. See dots-and-bars glyphs, Long Count notation, and place-value breakdowns.
Miracle Probability Calculator — Calculate the probability of "miraculous" events — birthday paradox, lottery odds, coincidence probability, and Littlewood's Law of Miracles.
One's Complement Calculator — Convert between decimal and one's complement binary representation. View bit flipping, sign detection, range tables, and comparison with two's complement.
Pi (π) Explorer & Calculator — Explore pi — view digits, approximate with Leibniz/Machin/Monte Carlo methods, calculate circle area, circumference, and annulus area interactively.
Polish Notation Converter & RPN Evaluator — Convert between infix, prefix (Polish), and postfix (Reverse Polish) notation. Evaluate RPN expressions with step-by-step stack traces.
Potato Paradox Calculator — Explore the Potato Paradox — see how 100 kg of 99% water potatoes become 50 kg at 98% water. Generalize with any weight and water percentage.
RSA Encryption Demo Calculator — Explore RSA encryption with small primes — generate keys, encrypt and decrypt messages, see modular exponentiation step by step.
Scatter Plot & Regression Calculator — Plot data points, compute Pearson correlation, linear regression, R², residuals, standard error, and outlier detection interactively.
Significant Figures Calculator — Count significant figures in any number, round to N sig figs, and perform arithmetic with proper significant figure rules. Digit-by-digit analysis.
Subset & Power Set Calculator — Generate all subsets (power set) of a set, count by size with C(n,k), view binary encodings, and solve subset-sum problems interactively.
Two's Complement Calculator — Convert between decimal and two's complement binary for 8, 16, 32, 64-bit widths. View hex, octal, range, overflow detection, and arithmetic operations.