Tools › Text & Data › Number Base Converter
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Binary, Octal, Decimal & Hex Converter
Type a number in any base and see it in all the others. Very large integers are supported.
How it works
Computers store numbers in binary, and programmers write them in hexadecimal because one hex digit equals exactly four bits. Octal is still used for Unix file permissions. Prefixes 0x (hex), 0b (binary) and 0o (octal) are recognised and override the selected base. Conversion uses arbitrary-precision integers, so results are exact even beyond 64 bits.
Frequently asked questions
How do I convert binary to decimal?
Multiply each bit by a power of two, starting from 1 on the right, and add them up. For example 1011 = 8 + 2 + 1 = 11.
Why is hexadecimal used so much?
Each hex digit represents four bits, so a byte is always two hex digits, which is compact and easy to read.
Does it handle negative numbers or fractions?
Negative integers work with a leading minus sign. Fractions are not supported.
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