Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal.
Every number can be represented in different bases. The base (or radix) tells you how many
distinct digits are available before "rolling over" to the next place value. Binary (base 2) uses only 0 and 1 and is the native language of computer
hardware. Octal (base 8) uses digits 0–7 and appears in Unix file
permissions (e.g., chmod 755). Decimal (base 10) is everyday
arithmetic. Hexadecimal (base 16) uses 0–9 and a–f, and is ubiquitous in
memory addresses, color codes (#ff5500), and byte-level data.
This tool uses JavaScript's BigInt type for all arithmetic, so it handles
arbitrarily large integers without precision loss — no 53-bit limit like Number.
Link to this tool with values filled in
Everything after the # stays in your browser — it is never sent to a server — so a
link like this opens the tool ready to go without the values travelling anywhere but the address
bar:
https://crunchify.net/tools/base-converter#value=ff&base=16
Join the settings with &, and percent-encode each value so that spaces,
newlines and any #, &, = or % inside one
do not break the link. Leave a setting out to accept its default. If a setting is not recognised,
the page says so rather than quietly ignoring it.
value(alsoinput,number,norq) — text, up to 300 characters, required. The number to convert, written in the base named below.base(alsofromorradix) — 2, 8, 10 or 16, defaults to10. Which base the value is written in: binary, octal, decimal or hex.
How do I convert binary to decimal?
Multiply each bit by 2 raised to its position (right to left, starting at 0), then sum. Example: 1011 = 1×8 + 0×4 + 1×2 + 1×1 = 11. Or paste the binary number in the Binary field and read the Decimal result.
How do I convert decimal to hexadecimal?
Repeatedly divide by 16, recording remainders (0–9 as digits, 10–15 as a–f), then read the remainders in reverse. Example: 255 ÷ 16 = 15 remainder 15 → FF. Or just type 255 in the Decimal field here.
What is hexadecimal used for?
Hexadecimal (base 16) compactly represents binary data — one hex digit = 4 bits. It is used in memory addresses, color codes (#ff5500), byte values in protocols, and debugging output. Two hex digits represent one byte (0x00–0xFF = 0–255).
What is octal used for?
Octal (base 8) appears mostly in Unix/Linux file permissions. chmod 755 means owner = 7 (rwx), group = 5 (r-x), others = 5 (r-x). Each octal digit represents 3 bits.
Related Tools
Updated August 27, 2026