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Number Base Converter

Keep binary, octal, decimal, hex, and a custom base in sync in this tab — BigInt keeps large integers exact.

Processed in your browser

Conversion runs in this browser with BigInt. We do not send values.
Base conversion finishes in this browser. Integers stay on this device and are not uploaded.

Digits 0 and 1 only; optional 0b prefix.

Digits 0–7; optional 0o prefix.

Standard decimal integers; leading minus allowed.

Digits 0–9 and A–F; optional 0x prefix.

Integer from 2 to 36.

Digits 0–9 then A–Z (case-insensitive).

Enter an integer in any field, then convert.

Features

Four standard bases

Binary, octal, decimal, and hex update together.

Custom bases 2–36

Any radix with digits 0–9 then A–Z.

BigInt precision

Exact beyond Number.MAX_SAFE_INTEGER.

Stays in the browser

Math runs on this device. Values are not uploaded.

How to use

  1. Enter an integer in Binary, Octal, Decimal, or Hex.
  2. Press Convert, or leave the field — the other bases update.
  3. Optionally set a custom base 2–36, then copy what you need.

Why this tool

Runs in the browser

Core work finishes in this tab.

No upload

Pasted text and local files are not sent away for processing.

Free, no account

The core path has no signup wall.

Immediate

There is no upload-and-wait queue.

10 languages

The same tool ships in ten languages.

Readable failures

Broken input returns a reason, not a blank screen.

FAQ

Are values uploaded?
No. Conversion runs in this browser with BigInt.
Do large integers lose precision?
No. BigInt is exact beyond Number.MAX_SAFE_INTEGER.
Are custom bases supported?
Yes, bases 2–36 with digits 0–9 then A–Z.
Is it free? Do I need an account?
Yes, it is free. No account is required.

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