# Math

> Calculators and number tools — primes, random numbers, Roman numerals and more, computed instantly in your browser.

URL: https://acrafto.com/en/math/

Tools are interactive browser apps; there is no public API, no endpoints to call and no server-side processing. To use a tool, open its HTML page in a browser.

- [Percentage Calculator](https://acrafto.com/en/percentage-calculator/index.md): Percentage calculator that shows its working: percent of a number, percentage change, percentage points, discounts, margin and shares of a total.
- [Random Number Generator](https://acrafto.com/en/online-random-number-generator/index.md): Free random number generator with secure or reproducible seeded draws, six distributions, weights, dice notation and live statistics. 100% in your browser.
- [Prime Number Generator](https://acrafto.com/en/prime-number-generator/index.md): Generate all prime numbers in a range or select N random primes. Uses the Sieve of Eratosthenes for instant, client-side calculations – no server, no waiting.
- [Number System Converter](https://acrafto.com/en/number-system-converter-negative-numbers/index.md): Convert between BIN, HEX, DEC, OCT number systems. Supports two's complement, 8-64 bit widths, and large numbers. Free online tool for developers.
- [Roman Numeral Converter](https://acrafto.com/en/roman-arabic-numeral-converter/index.md): Convert between Arabic and Roman numerals up to 9,999,999. Roman numeral calculator for I, V, X, L, C, D, M with vinculum notation.
- [Verify a Random Draw](https://acrafto.com/en/verify-random-draw/index.md): Check that a random draw was not tampered with. Paste the certificate code and see whether the seed, the fingerprint and the numbers agree.