Number base converter
Convert numbers between binary, octal, decimal, and hexadecimal instantly. Supports arbitrarily large numbers with BigInt precision.
- 100% free
- No sign-up
- No limits
- Instant results
Valid digits: 0-9
Enter a number above
Enter a number above
Enter a number above
Enter a number above
- Binary, octal, decimal, and hex conversion
- Real-time conversion as you type
- BigInt support for numbers beyond 53 bits
- Grouped bit visualization for binary
- Copy any result with one click
- 100% browser — no server calls
What is Number Base Converter?
A number base converter is a tool that translates numbers between different numeral systems — binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16).
These number systems are fundamental in computing and programming. Binary is the language computers use internally, representing data as sequences of 0s and 1s. Octal was historically used in Unix file permissions and some older systems. Decimal is the standard human-readable number system. Hexadecimal is widely used in programming for memory addresses, color codes (#FF5733), MAC addresses, and any context where compact binary representation matters. This tool converts between all four bases simultaneously — enter a number in any base and instantly see its representation in the other three. It supports arbitrarily large numbers using JavaScript BigInt, meaning you can convert values well beyond the 53-bit integer limit (9,007,199,254,740,991) that standard number types impose. The bit visualization feature displays binary output in grouped nibbles (4-bit groups) with bit position labels, making it easy to inspect individual bits for debugging, bitwise operations, or learning digital logic. Everything runs in your browser with zero server calls.
How to use Number Base Converter
- 1
Select your input base
Click one of the four base buttons — Binary (2), Octal (8), Decimal (10), or Hexadecimal (16) — to tell the tool what format your number is in. The input field will only accept valid digits for the selected base.
- 2
Enter your number
Type or paste your number into the input field. The tool validates each character in real time and shows an error if you enter an invalid digit for the selected base. Conversions to all four bases appear instantly below as you type.
- 3
Copy or inspect the results
Click the Copy button next to any conversion result to copy it to your clipboard. For binary output, scroll down to the bit visualization to see individual bits grouped into nibbles with position labels — useful for understanding bitwise operations and data structures.
Everything this tool
does for you
- Simultaneous conversion to binary, octal, decimal, and hexadecimal from any input base
- Real-time conversion that updates instantly as you type each character
- BigInt support for numbers beyond the 53-bit JavaScript integer limit
- Input validation that only accepts valid digits for the selected base
- Visual bit display with 4-bit nibble grouping and bit position labels
- One-click copy button on every conversion result
- Zero server calls — all conversion runs entirely in your browser
- Clean prefix display (0b, 0o, 0x) for easy identification of number bases
Related free tools
Frequently asked questions
This tool fixed one thing.
Now fix the whole site.
Our scanner runs 240+ checks across 10 audit areas, ranks every issue by the score points it costs, and hands you the code to paste.
Run a free audit