Number Base Converter
Convert between binary, decimal, hex, and octal
Calculator
How to Use
Convert numbers between bases
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Input the number to convert
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Choose binary, decimal, hex, or octal
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Frequently Asked Questions
Base determines how many digits are used. Decimal (base-10) uses 0-9. Binary (base-2) uses 0-1. Octal (base-8) uses 0-7. Hexadecimal (base-16) uses 0-9 and A-F. Computers use binary internally; hex is common in programming.
Divide by 2 repeatedly, record remainders. 13 ÷ 2 = 6 r1, 6 ÷ 2 = 3 r0, 3 ÷ 2 = 1 r1, 1 ÷ 2 = 0 r1. Read remainders bottom-up: 1101. Or: 13 = 8+4+1 = 2³+2²+2⁰ = 1101.
Hex is compact and maps perfectly to binary (4 bits = 1 hex digit). FF in hex = 11111111 in binary = 255 in decimal. Memory addresses, color codes (#FF0000), and byte values are more readable in hex than binary.
Each position is a power of 2 (right to left: 1, 2, 4, 8, 16...). Add positions with 1. Binary 1011 = 8+0+2+1 = 11. For 8-bit numbers, max is 11111111 = 255. For signed numbers, leftmost bit indicates negative.
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