Number Base Converter

Convert numbers between binary, octal, decimal and hex.

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Programmers and students constantly move numbers between bases — decimal for humans, binary for hardware, hexadecimal for colours and memory addresses. The Number Base Converter takes a value in any common base and shows it simultaneously in binary, octal, decimal and hexadecimal, removing the mental arithmetic.

How to use the Number Base Converter

  1. Enter a number and tell the tool which base it is in.
  2. See it instantly expressed in all four bases.
  3. Copy whichever representation you need.

Why different bases exist

We count in base-10 because we have ten fingers, but computers are built from switches that are either on or off, which is base-2 (binary). Binary numbers get long quickly, so programmers use hexadecimal (base-16) as a compact shorthand — every hex digit stands for exactly four binary digits. Octal (base-8) is a similar shorthand from older systems. Being able to flip between them is fundamental to low-level programming, debugging, and understanding things like colour codes and file permissions.

Tips for base conversion

  • Hex uses 0–9 then A–F for the values ten to fifteen.
  • One hex digit equals four binary digits, which is why hex is so handy.
  • Binary grows fast; the decimal 255 is 11111111 in binary but just FF in hex.
  • Double-check the input base so the tool interprets your number correctly.

All conversion is done in your browser, so nothing is uploaded.

Quick reference

BaseValue of 255
Binary (2)11111111
Octal (8)377
Decimal (10)255
Hex (16)FF
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