- What are the four main number bases?
- Binary (base 2) uses digits 0–1 and is the language of computers. Octal (base 8) uses digits 0–7, common in Unix file permissions. Decimal (base 10) uses digits 0–9, the human counting system. Hexadecimal (base 16) uses 0–9 and A–F, widely used in programming for memory addresses and colors.
- How do I convert decimal to binary?
- Repeatedly divide the decimal number by 2 and record the remainders from bottom to top. Example: 13 ÷ 2 = 6 R1, 6 ÷ 2 = 3 R0, 3 ÷ 2 = 1 R1, 1 ÷ 2 = 0 R1 → binary is 1101. The converter shows this result instantly. Select Decimal input, enter 13, and see 1101 in binary.
- What is hexadecimal used for in programming?
- Hexadecimal is used for memory addresses (0xFF00A2), color codes in CSS/HTML (#3b82f6 = RGB 59,130,246), Unicode code points (U+1F600), file magic bytes, and bit masks. Each hex digit represents exactly 4 bits, making hex a compact and readable representation of binary data.
- What do Unix file permission numbers mean?
- Unix permissions use octal. 755 in octal: 7 = rwx (read+write+execute) for owner, 5 = r-x for group, 5 = r-x for others. In binary: 111 101 101. The chmod command accepts these octal values directly. Convert 755 from octal to binary to see the individual permission bits.
- How does base 36 work?
- Base 36 uses digits 0–9 and letters A–Z (26+10 = 36 symbols). It is the most compact base using only alphanumeric characters and is used for URL shorteners, unique IDs, and serial numbers where readability matters. The number 123456789 in base 36 is "21I3V9".
- What is the maximum number this converter handles?
- The converter uses JavaScript's standard Number type (IEEE 754 double precision), which safely handles integers up to 2⁵³ − 1 (9,007,199,254,740,991 in decimal). For very large numbers (cryptographic keys, large memory addresses), you would need a big integer library.
- Why does 0xFF equal 255 in decimal?
- Each hex digit represents 4 bits. 0xFF = F × 16¹ + F × 16⁰ = 15 × 16 + 15 × 1 = 240 + 15 = 255. In binary, FF = 11111111 = 8 bits all set to 1. 255 is the maximum value of an 8-bit unsigned integer and the maximum single-channel RGB color component.