Number Base Converter

Convert between binary, octal, decimal, hex
This free online number base converter runs in your browser and is part of our Converters collection.

🔄 Number Base Converter

Convert numbers between binary, octal, decimal, and hexadecimal

Examples:

Decimal: 255 = Binary: 11111111 = Octal: 377 = Hex: FF

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Instant In-Browser Execution Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever No subscription fees, no signups, and no software installations.

How to Use the Online Number Base Converter

1 Choose Input Number Base

Select the originating numeral system: Binary (Base 2), Octal (Base 8), Decimal (Base 10), Hexadecimal (Base 16), or Custom Base (2–36).

2 Enter Value to Convert

Type or paste the number into the source input field.

3 Inspect Synchronized Multi-Base Matrix

As you type, the converter automatically updates all standard computer science bases simultaneously in real time.

4 Copy Output with Prefixes

Copy clean numbers or formats with standard programming prefixes (`0b` for binary, `0x` for hex, `0o` for octal).

Frequently Asked Questions

Common questions about using this free online number base converter.

What characters are used for bases higher than 10? ▾
Bases 11 through 36 use standard Latin letters A through Z to represent digits 10 through 35 (e.g. in Hexadecimal, A=10, B=11, C=12, D=13, E=14, F=15).
Does this converter support arbitrarily large numbers without precision loss? ▾
Yes. Conversions are calculated using JavaScript native `BigInt` arbitrary-precision arithmetic, allowing you to convert 256-bit cryptographic keys and large hashes without precision loss.
Can I convert fractional floating-point numbers between bases? ▾
Yes. The converter supports fractional radix points (e.g. converting `1010.101` binary to decimal `10.625`).
What is the Two's Complement representation? ▾
For negative numbers, the tool displays standard signed two's complement binary representations for 8-bit, 16-bit, 32-bit, and 64-bit integer widths.

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