Number Base Converter
Convert between binary, octal, decimal, and hexadecimal. Type in any field to update all others.
Bit breakdown
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8-bit binary
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16-bit binary
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Number system reference
- Binary (base 2): digits 0–1. Used in digital logic and CPU instructions.
- Octal (base 8): digits 0–7. Used in Unix file permissions.
- Decimal (base 10): digits 0–9. The everyday number system.
- Hexadecimal (base 16): digits 0–9 and A–F. Used in memory addresses, colours, and byte representations.
Frequently Asked Questions
What is binary (base 2)?
Binary is a number system that uses only two digits: 0 and 1. It is the foundation of all digital computing because transistors can be in two states: off (0) or on (1). The decimal number 42 is 101010 in binary.
What is hexadecimal (base 16)?
Hexadecimal uses 16 symbols: 0–9 and A–F (where A=10, B=11, C=12, D=13, E=14, F=15). It is widely used in programming, HTML colour codes, and memory addresses because it compactly represents binary data — one hex digit represents exactly 4 binary bits.
What is octal (base 8)?
Octal uses digits 0–7. It was historically used in computing because it maps cleanly to groups of 3 binary bits. It is still used in Unix/Linux file permissions, where permissions are represented as 3-digit octal numbers like 755 or 644.