Number Base Converter

Number Base Converter — bin, oct, dec, hex

This tool instantly converts numbers between the four main numeral systems used in programming and computer science.

Numeral systems

• Binary (bin, 2) — digits 0 and 1, used in computer architecture;
• Octal (oct, 8) — digits 0–7, used in Unix file permissions;
• Decimal (dec, 10) — the familiar base-10 system;
• Hexadecimal (hex, 16) — digits 0–9 and A–F, widely used in CSS colors and memory addresses.

Frequently Asked Questions

• How do I convert the decimal number 255 to binary, octal and hexadecimal?

  Select "Decimal (Dec)" as the source system and enter 255. The converter instantly shows all results: binary (bin) — 11111111, octal (oct) — 377, hexadecimal (hex) — FF. The number 255 is the maximum value for one byte (8 bits) and appears frequently in networking and color codes.

• Can the tool convert negative numbers or fractions?

  The current version supports only non-negative integers. For negative numbers or floating-point values you would need a specialised mathematical tool. For the most common tasks in networking and programming — such as IP subnets, memory addresses and color codes — working with whole positive numbers covers virtually all use cases.

• Which letters are valid when converting from hexadecimal?

  In hexadecimal mode you can enter digits 0–9 and the letters A through F (case-insensitive — both uppercase and lowercase are accepted). Letters G and beyond are not part of the hex alphabet. For example, the value #FA0C3D is a valid hexadecimal input and will be processed correctly.