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Integer Base Converter

Use BigInt parsing to preserve integers beyond JavaScript's safe-number range. Optional 0b, 0o, and 0x prefixes are accepted only when they match the selected source base.

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Tool guide

What is Integer Base Converter?

Integer Base Converter uses BigInt to convert signed integers among binary, octal, decimal, and hexadecimal without JavaScript Number precision loss. Characters and prefixes are validated against the selected source base. Fractions and exponent notation are excluded so precision and meaning remain explicit. Common workflows include the following. View a decimal identifier in hexadecimal. Convert between binary permission bits and decimal values. Verify the complete representation of a very large integer. The page also documents input boundaries, output behavior, and practical cautions so you can review the result before putting it into an application, configuration, test, or production workflow.

When to use it

  • View a decimal identifier in hexadecimal.
  • Convert between binary permission bits and decimal values.
  • Verify the complete representation of a very large integer.

How to use it

  1. Choose source and target bases.
  2. Enter a signed integer without a decimal point.
  3. Convert without Number precision loss.
  4. Load one of the realistic examples first to verify the selected options and processing direction before replacing it with your own data.
  5. Review the output, status message, and documented limits; copy, download, or continue only after the result matches your expectation.

Runnable examples

The “Example 1” and “Example 2” buttons load the matching inputs. They cover different structures, directions, or boundaries and can be run directly in the workspace.

Example 1

900719925474099312345

Example 2

-170141183460469231731687303715884105727

Input rules

  • Input must be an integer and may include a leading sign.
  • 0b, 0o, and 0x prefixes must match the selected source base.
  • Fractions, exponent notation, and spaces inside digits are rejected.
  • Text input is counted before processing and is limited to 10,000 characters on this page; file modes apply the separate file limit shown in the workspace.
  • Fractions and exponent notation are rejected.

Output rules

  • Output uses the standard digits for the target base.
  • Hexadecimal letters are uppercase.
  • Conversion uses BigInt and never passes through floating-point Number.
  • Output reflects only the current input, direction, and options; rerun after changing a mode or value instead of treating an earlier result as current.
  • Only bases 2, 8, 10, and 16 are available.

Limitations and cautions

  • Fractions and exponent notation are rejected.
  • Only bases 2, 8, 10, and 16 are available.
  • Whitespace inside a number is invalid.

How your data is handled

Integer parsing and base conversion are performed locally without storing or uploading values.

FAQ

Can it handle very large integers?

Yes. It uses BigInt rather than floating-point Number values.

Are fractions supported?

No. This version intentionally supports integers only to avoid ambiguous rounding rules.

Can I include a prefix?

Yes for matching bases: 0b for base 2, 0o for base 8, and 0x for base 16.

Are integers beyond the safe-number range exact?

Yes. The parser uses BigInt rather than converting through JavaScript Number.

How are negative values represented?

The result uses a leading minus sign, not a fixed-width two's-complement representation. A target system must define a bit width separately.

Why are fractional values unsupported?

Fractions introduce repeating digits, precision, and rounding choices. This version stays integer-only so results remain unambiguous.

Updated: 2026-08-02