Tools / Number Base Converter
Number Base Converter
Type a number in any base -- binary, octal, decimal, or hexadecimal -- and all four fields update instantly. The signed 32-bit panel shows how the value is stored in memory, and a bit visualization appears for values that fit in a single byte.
Signed 32-bit interpretation
Bit visualization (8-bit)
How positional notation works
Every positional number system uses a fixed radix (base). In base 10 (decimal), each digit position represents a power of 10. In base 2 (binary), each position is a power of 2 -- so the value 1010 in binary means 1×8 + 0×4 + 1×2 + 0×1 = 10 in decimal.
Hexadecimal (base 16) is the format you will encounter most in CTF challenges. One hex digit represents exactly four bits, making it compact for representing binary data. Memory addresses, file headers (magic bytes), and color values are all commonly expressed in hex. For example, the PNG magic bytes are 89 50 4E 47.
The signed 32-bit display shows how computers store integers using two's complement. The highest bit acts as a sign bit: if it is set, the number is negative. This is why casting a large unsigned value like 0xFFFFFFFF to a signed 32-bit integer gives -1.
Challenges solved with this tool: picoCTF 2024 -- BinHexa, where you must convert between binary and hex on a timed terminal.