Number Base Converter
Convert between Binary, Octal, Decimal, and Hexadecimal — all four bases at once.
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Everything you need to know
All Four Bases, Instantly
Enter a number in any base — binary, octal, decimal, or hexadecimal — and see it converted to all other bases in real time. Digits are grouped for readability (groups of 4 for binary and hex, groups of 3 for octal and decimal). Supports arbitrarily large numbers.
Why Developers Need Base Conversion
Hexadecimal is everywhere in programming: CSS colors (#FF5733), memory addresses, byte values. Binary is how CPUs think. Octal appears in Unix file permissions (chmod 755). Being able to convert between them quickly is a daily workflow need for developers, sysadmins, and hardware engineers.
Common Conversions Quick Reference
- 255 = FF (hex) = 1111 1111 (binary) = 377 (octal)
- 128 = 80 (hex) = 1000 0000 (binary) = 200 (octal)
- 65535 = FFFF (hex) = 1111 1111 1111 1111 (binary)
- chmod 755 = rwxr-xr-x (owner read/write/execute, others read/execute)
Bit Info Panel
The converter also shows how many bits and bytes are needed to represent the value, plus the maximum unsigned value at that byte width. Useful for choosing data types (uint8, uint16, uint32, etc.).
Related Tools
Need to convert data sizes? Use the Data Converter. For advanced math operations, try the Scientific Calculator. Percentage math is at the Percentage Calculator.