Number Base Converter Online – Decimal, Hex & Binary

Local only

Convert whole numbers between decimal, hexadecimal, binary, and octal without losing large integer precision.

3 chars · 1 line

62 chars · 4 lines

Converted integer bases with exact BigInt precision

Integer base conversion guide

Convert integers between decimal, hexadecimal, binary, and octal

Paste a whole number into the converter above using ordinary decimal digits or a 0x, 0b, or 0o prefix. VetaTool returns the same integer in decimal, hexadecimal, binary, and octal with browser-native BigInt precision, so large identifiers and bit masks are not rounded through JavaScript Number values. This tool is free to use. No account or payment is required.

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What you can do here

  • Decimal integer input
  • 0x hexadecimal input
  • 0b binary input
  • 0o octal input
  • BigInt precision for large integers
  • Browser-local processing

Steps

  1. Paste a decimal integer, or prefix hexadecimal with 0x, binary with 0b, or octal with 0o.
  2. Review the decimal, hexadecimal, binary, and octal forms produced together.
  3. Keep the sign when converting negative integers; prefixes are placed after the minus sign in output.
  4. Copy or download the conversion result without uploading the value.

Recognize the input base from its prefix

Unprefixed digits are treated as decimal. A 0x prefix selects hexadecimal, 0b selects binary, and 0o selects octal. Prefix matching is case-insensitive, while hexadecimal output uses uppercase A–F for easier scanning.

Digits are validated against the detected base before conversion, so values such as 0b102 or 0o89 are rejected instead of being partially parsed.

Keep large integer conversions exact

The converter uses BigInt rather than JavaScript Number for integer parsing and formatting. That avoids precision loss above 9,007,199,254,740,991, which matters for large IDs, 64-bit values, masks, and protocol fields copied from logs or source code.

This tool intentionally handles whole integers only. Floating-point numbers, scientific notation, fractions, and byte-string decoding are separate problems and are not guessed here.

  • Translate a decimal permission or flag value into binary for bit inspection.
  • Convert hexadecimal constants from logs into decimal for API or database checks.
  • Reformat large 64-bit-style integer values without Number rounding.

Convert numeric representations locally

Parsing and base conversion run entirely in your browser. The integer is not sent to a VetaTool processing server, and the result can be copied or downloaded locally.

Hexadecimal to other bases example

The hexadecimal value 0xFF represents the same integer as decimal 255, binary 11111111, and octal 377.

Hexadecimal input

0xFF

Converted bases

Decimal: 255
Hexadecimal: 0xFF
Binary: 0b11111111
Octal: 0o377

Common questions

Frequently asked questions

Which number bases are supported?

The tool accepts decimal, hexadecimal with 0x, binary with 0b, and octal with 0o, then displays all four forms together.

Can it convert integers larger than Number.MAX_SAFE_INTEGER?

Yes. Conversion uses BigInt, so whole-number values larger than JavaScript's safe Number range keep their exact digits.

Are negative integers supported?

Yes. Add a leading minus sign before the decimal digits or base prefix, such as -42 or -0x2A.

Does it convert hexadecimal text bytes?

No. Number Base Converter treats the input as one integer. Use Hex Encoder & Decoder when hexadecimal pairs represent UTF-8 bytes or text data.

Keep working

Hex Encoder & Decoder OnlineEncode UTF-8 text as hexadecimal bytes or decode hexadecimal byte sequences back to text.Base64 Encoder & Decoder OnlineEncode text as Base64 or Base64URL when the task is transport encoding rather than integer notation.Hash Generator Online – MD5 & SHAGenerate fixed-length text digests when you need a hash rather than another representation of the same integer.

Looking for broader references? Browse all developer guides.