Number Base Converter
A Number Base Converter converts an integer between binary, octal, decimal, hexadecimal, and any custom base from 2 to 36, updating every representation live as you type — computed with BigInt in your browser for arbitrary-size values.
About Number Base Converter
Type a value into any field — binary, octal, decimal, hex, or a custom base you choose (2 to 36) — and every other base updates instantly. It uses BigInt internally, so 64-bit hex constants and huge decimals convert without precision loss, and negative values are supported. Invalid digits for the chosen base are flagged inline. Everything runs locally; nothing is sent anywhere.
What Number Base Converter does
- Binary, octal, decimal, hex, plus any base 2 to 36
- Live two-way conversion across every field
- BigInt precision for 64-bit and larger values
- Negative-number support
- Inline validation of invalid digits
- Runs entirely in your browser — nothing uploaded
When to reach for Number Base Converter
- Converting a hex color or memory address to decimal
- Reading a binary bitmask as decimal or hex
- Checking a permission or flag value across bases
- Teaching or learning positional number systems
How to use Number Base Converter
- 01
Pick any field
Type into binary, octal, decimal, hex, or your custom base.
- 02
Read the others
Every other base updates live as you type.
- 03
Copy
Copy any representation with its copy button.
When to use Number Base Converter vs alternatives
| Alternative | Use Number Base Converter when… | Use the alternative when… |
|---|---|---|
| A programmer calculator | you want all bases visible at once and a shareable web page, no app to open. | you need bitwise operations (AND/OR/shift), which a calculator provides. |
| parseInt / toString(radix) in a console | you want a UI and correct handling of values beyond 2^53. | you're already scripting and a one-liner is enough. |
Frequently asked questions
How do I convert binary to decimal?
Does it handle very large numbers?
What's the maximum base?
Can it convert negative numbers?
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