Binary
Uses only 0 and 1; each place is a power of 2.
Number Base Converter — Binary, Octal, Decimal, Hex
Convert between binary, octal, decimal, and hexadecimal values in one place. Choose the input base and see every result instantly.
Number Base Converter
Convert decimal, binary, octal, and hexadecimal values instantly.
Converted values
Binary (2)
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Octal (8)
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Decimal (10)
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Hexadecimal (16)
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A number base is a different way to write the same quantity
Programming, debugging, and digital systems often move between decimal, binary, octal, and hexadecimal. This converter lets you choose the input base once and then shows all four representations together, which is useful for code values, bit patterns, and quick checks.
Base rules
Octal
Uses digits 0 through 7; each place is a power of 8.
Hexadecimal
Uses 0-9 and A-F; each place is a power of 16.
How to use
- Choose the base that your input value is written in.
- Enter the value and the binary, octal, decimal, and hexadecimal results appear instantly.
- If a digit is not valid for the selected base, correct the input and try again.
Frequently asked questions
What is FF in decimal?
Hexadecimal FF is decimal 255. F represents 15, so FF = 15×16 + 15.
Why is 2 invalid in binary?
Binary can only use 0 and 1. Digits 2 and above belong to decimal or other bases, not base 2.
Does this convert fractional values?
This tool is designed for integer base conversion. Fractional base conversion follows additional rules.
This tool is for general arithmetic. For official figures such as taxes or finance, confirm with the relevant authority.