Color & Numbers
Color models, number bases, random numbers, percentages, unit conversion.
Number to Words Converter
This number to words converter spells out figures for cheques, contracts and invoices.
Bitwise Calculator
This bitwise calculator shows AND, OR, XOR and shifts with the bits lined up.
Reverse Hex (Endianness Swapper)
This tool swaps the byte order of a hex value, converting between big and little endian.
Number Sorter
This number sorter orders numbers properly, and gives you the sum, mean and median.
Roman Numeral Converter
This Roman numeral converter works in both directions, with the standard subtractive form.
IP Address Converter
This IP converter turns an address between dotted, decimal, hex, octal and binary forms.
CIDR / Subnet Calculator
This subnet calculator works out the network, broadcast, mask and host range from a CIDR block.
Credit Card Number Validator (Luhn)
This validator runs the Luhn check on a card number and identifies the issuer.
Color Converter (HEX / RGB / HSL / HSV / CMYK)
A color converter for HEX, RGB, HSL, HSV and CMYK, with a built-in WCAG contrast checker.
Number Base Converter
A number base converter for binary, hex, decimal, octal, Roman numerals, balanced ternary, negabinary and more.
Random Number Generator
A random number generator for cryptographically secure integers in any range, one at a time or in bulk, with optional no-repeats.
Percentage Calculator
A percentage calculator for three everyday calculations: X% of Y, X as a percent of Y, and percentage change between two numbers.
Unit Converter
Convert between units of length, weight, temperature, area, volume, speed, time, data storage, pressure and energy instantly.
Tint and Shade Generator
Build a full palette ramp of tints, shades and tones from one colour, and export it as CSS, SCSS or JSON.
Color Desaturation Tool
Fade a colour toward grey in even steps, and see how zero saturation differs from a true greyscale conversion.
About Color & Numbers
Handy converters and calculators for colors and numbers: colors between HEX, RGB, HSL, HSV and CMYK with a contrast checker, a tint and shade generator that turns one color into a full palette ramp ready to export as CSS or SCSS variables, and a desaturation tool that shows why zero saturation and a true greyscale conversion are not the same operation. On the number side, integers between binary, octal, decimal and hexadecimal at arbitrary size, bitwise arithmetic, IP address and subnet conversion, Roman numerals, cryptographically random integers, everyday percentage calculations, and a unit converter covering length, weight, temperature, volume, speed, data storage and more.
Everything on this page runs directly in your browser — none of your input is uploaded to a server.