Number & Base Tools Tools

Free online number tools — a 2x2/3x3 matrix calculator for determinant, inverse and multiplication, computed entirely in your browser.

6 tools

Matrix Calculator

Add, subtract, multiply, transpose, and find the determinant or inverse of a 2x2 or 3x3 matrix. No data ever leaves your device.

Random Numbers

Draw whole numbers from any range using your device's cryptographic random source, with unique-values mode and the modulo bias rejected rather than ignored.

Dice Roller

Roll d4 through d100 with standard dice notation like 2d6+3, a running history, and cryptographically random results. No physical dice required.

Fibonacci Generator

Generate the Fibonacci sequence up to F(200) with exact BigInt precision. Shows golden-ratio convergence, a visual bar chart, and copy as CSV or lines.

Prime Checker

Check whether any positive integer is prime, with the full prime factorisation when it is not. Trial division to ⌈√n⌉ — deterministic and exact.

Also in Number & Base Tools

Tools from other categories tagged with Number & Base Tools

Matrix Rotation

Input a 2D matrix, choose 90°/180°/270° CW or CCW rotation. See the visual index shift and get the C++ implementation.

Why These Tools

Matrix Calculator exists because computing a 3×3 inverse by hand is exactly the kind of arithmetic where a single sign error invalidates the whole page of work. It runs the same cofactor-expansion method a linear algebra course teaches, verified against NumPy's own linalg functions during development rather than trusted on faith. Matrix Rotation Simulator sits here too by cross-link, filed primarily under Competitive Programming, for the different question of how a grid's indices shift under a 90-degree turn rather than what its determinant or inverse works out to. Factorial, Fibonacci, and base-conversion tools are next in line.