Code and Number Converters

How to use it

Each converter has its own page with a short explanation, a table of common values and answers to common questions.

What each converter is for

• Roman numerals are still used for clock faces, book chapters, film sequels, building dates and the Super Bowl. They use seven letters: I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). A smaller letter before a larger one is subtracted, so IV is 4 and XC is 90.
• Morse code turns each letter into short and long signals. It was designed in the 1830s and 1840s for the telegraph and is still used in aviation, amateur radio and as a distress signal: SOS is three dots, three dashes and three dots.
• Binary is how computers store numbers and text, using only 0 and 1. Eight binary digits make a byte, and the letter A is the byte 01000001, which is 65 in decimal.
• ASCII and Unicode give every character a number. ASCII has 128 characters, and Unicode extends the idea to every writing system and to emoji.
• HEX, RGB and HSL describe colours on a screen. HEX and RGB hold the same red, green and blue values, written in base 16 or base 10.
• Number bases change the way a number is written without changing its value. Decimal 255 is 11111111 in binary, 377 in octal and FF in hexadecimal.

Handy facts

• Hexadecimal uses the digits 0 to 9 and the letters A to F, so one hex digit holds four bits.
• The 3-digit colour shorthand doubles each digit: #F80 means #FF8800.
• Roman numerals have no zero, and the standard form stops at 3999.

All the converters run in your browser. Nothing you type is uploaded.

What people use it for

• Homework
• Puzzles
• Web design
• Learning how computers store data

Questions

Last updated 2026-10-24. Free to use, no sign-up. Made by ficklestudio26.

More: Roman numerals Morse code Binary translator HEX to RGB Decimal to binary ASCII converter Unit converter