Number Base Converter — Free Online Tool
Convert a number between binary, octal, decimal, and hexadecimal.
About Number Base Converter
The Number Base Converter instantly translates a whole number between binary, octal, decimal, and hexadecimal. Choose the base your value is written in, and the tool displays all four representations together, which is ideal for low-level programming, debugging, and learning how computers store numbers.
Input is validated against the digits allowed for each base, so mistakes are caught before conversion, and negative numbers are supported with a leading minus sign. Everything runs locally in your browser, making conversions fast and completely private.
How to Use Number Base Converter
- Type the number you want to convert into the input field.
- Select the base your number is written in from the dropdown.
- Click 'Convert' to compute the value in all four bases.
- Read the binary, octal, decimal, and hexadecimal results.
Key Features
Convert between binary, octal, decimal, and hexadecimal
Shows all four base representations simultaneously
Validates digits against the selected base before converting
Supports negative integers with a leading minus sign
100% client-side processing with instant results
Frequently Asked Questions
Which number bases are supported?
You can convert between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Pick the base of your input and the tool shows all four representations at once.
Does it handle negative numbers?
Yes. If you prefix your input with a minus sign, the tool converts the magnitude and prepends the sign to each result so negative values are represented consistently across all bases.
Why do I get an invalid number error?
Each base only allows certain digits. For example, binary accepts only 0 and 1, and hexadecimal accepts 0-9 and A-F. If your input contains characters outside the chosen base, the tool flags it.
Can it convert decimals or fractions?
No. This converter works with whole integers only. Fractional parts and decimal points are not supported.
Is the conversion done privately?
Yes. All math runs in your browser with JavaScript, so your numbers are never sent anywhere and conversion is instant.