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Convert integers between binary, octal, decimal, and hexadecimal in your browser, exactly, even for numbers beyond 2^53.
Enter one value and see binary, octal, decimal, and hexadecimal side by side, each with a copy button.
Uses BigInt, so values beyond Number.MAX_SAFE_INTEGER (2^53) are converted without rounding.
Supports a minus sign and the 0b, 0o, and 0x prefixes, but rejects a prefix that conflicts with the chosen base.
A digit outside the base (like 2 in binary or 8 in octal) is reported, never partly parsed.
When you use Number Base Converter, your data never leaves your browser. All transformations execute in-memory on your local machine with zero server uploads. Web assets are downloaded to run the tool, but your input data is never transmitted.
No. Everything is computed in your browser. The page does download the code needed to run the tool.
Up to 10,000 digits. Values are exact because BigInt is used instead of floating-point numbers.
No. Only whole numbers (integers), positive or negative, are converted.
It is an error. For example, 0x10 with the input base set to decimal is rejected instead of being silently reinterpreted. Change the input base or remove the prefix.
Whole numbers only, with an optional minus sign. A prefix for a different base is rejected, and changing the input base re-reads the same text in the new base. Large numbers are exact (BigInt). Hexadecimal is shown in uppercase. Processed locally in your browser.