Free Online Number Base Converter

Number base conversion rewrites the same value in different bases — binary, octal, decimal, hex, or any radix between 2 and 36.

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Base:

How to Use This Developer Tool

  1. Type a value into any of the binary, octal, decimal, or hex fields.
  2. The other fields update live with the same value in their base.
  3. Use the custom base field for anything from base 2 to base 36.
  4. Click any Copy button to grab a specific representation.

What Is a Number Base Converter?

Different bases suit different jobs: binary for bit-level masking, hex for memory addresses and CSS colour codes, decimal for human input, octal for traditional Unix file permissions (`chmod 755`). The values themselves are identical — only the textual representation changes between bases.

The converter shows all four common bases side by side and updates them live as you edit any field. A custom radix input covers everything between base 2 and base 36 (base 36 uses 0–9 and A–Z), which is the largest you can express with single ASCII characters. Useful for debugging packed flag fields, decoding a colour hex code into RGB integers, or just checking the binary representation of a tricky integer.

Frequently Asked Questions

What bases are supported?
Binary (2), octal (8), decimal (10), hex (16), and any base 2-36. Base 36 uses 0-9 and A-Z.
How do I convert decimal to binary?
Enter your decimal value in the decimal field; the binary, octal and hex outputs update live.
What about negative numbers?
Our tool handles signed decimals. For two's-complement representations at a fixed bit width, use a dedicated bitwise tool.

Published by the WeGotEveryTool team. We build and test every tool in-house and update pages when the underlying spec, formula, or recommendation changes.

Reviewed: May 2026. Disclaimer: this tool is provided as-is for general informational use. For decisions with material consequences (medical, legal, financial, security) verify results against a qualified professional source.

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