Free number base converter. Convert binary to decimal, hex to decimal, decimal to binary and more — all four bases update live in your browser.
A number base (or radix) determines how many distinct digits are used to write a value. This converter translates a whole number between the four bases programmers use every day: binary (base 2, digits 0–1), octal (base 8, digits 0–7), decimal (base 10, digits 0–9), and hexadecimal (base 16, digits 0–9 and A–F). Type a value into any of the four fields and the other three update instantly.
Pick the field that matches the number you already have. Want to know what FF is in decimal? Type FF in the hexadecimal box and read 255 from the decimal box. Need 13 in binary? Type it in decimal and read 1101. A leading 0x, 0o, or 0b prefix is accepted and stripped automatically, and you can group long values with underscores or spaces for readability.
0x1A = 26. Each hex digit represents 4 bits, so 1A is 0001 1010 in binary.11111111 = 255 = 0xFF — the largest value in a single byte.0x1000 = 10000000000000 in binary.Hexadecimal is compact and maps cleanly to bytes, which is why it shows up in color codes (#FF8800), memory addresses, MAC addresses, and hash digests. Binary reflects how hardware actually stores data, while octal still appears in Unix file permissions (e.g. chmod 755). Because the converter uses arbitrary-precision integers, it handles values far larger than a 64-bit number without losing accuracy, and it also supports negative integers. Everything runs locally in your browser — no value you enter is ever sent to a server.
Type or paste your hexadecimal value (for example FF or 0x1A) into the Hexadecimal field. The Decimal field updates instantly — FF becomes 255 and 1A becomes 26. The binary and octal equivalents are shown at the same time.
Enter your binary digits (only 0s and 1s) in the Binary field. For example, 1101 converts to 13 in decimal, and 11111111 converts to 255. The hexadecimal and octal values appear alongside it.
Yes. The converter uses arbitrary-precision (BigInt) arithmetic, so it converts numbers far larger than the usual 64-bit limit without rounding errors. It also supports negative integers and optional 0x, 0o, or 0b prefixes.
No. All conversion happens entirely in your browser using client-side JavaScript. Nothing you type is uploaded or stored.