Binary, Hex & Decimal Converter
Convert numbers between binary, decimal, hexadecimal, octal and any base from 2 to 36, with no size limit and the working shown. Also turns text into binary or hex and back.
Free · No sign-upHow to use Binary, Hex & Decimal Converter
- 1. Type a number into any box — binary, octal, decimal, hex or a custom base — and every other box updates as you type.
- 2. Use prefixes (0b, 0o, 0x), spaces or underscores freely; turn on digit grouping and uppercase hex to make long values easier to read.
- 3. See bit length, the two’s complement pattern for 8, 16, 32 or 64 bits (handy for negative numbers), and the step-by-step working for binary and hex.
- 4. Open Text ⇄ binary / hex to encode words as bytes or decode binary back to text. Copy any value or share a link.
Frequently asked questions
How do I convert binary to decimal?
Multiply each bit by its power of 2, starting from 2⁰ on the right, and add the results. For example 1011 = 1×8 + 0×4 + 1×2 + 1×1 = 11. The converter shows this working for numbers up to about a million.
How do I convert decimal to binary?
Divide the number by 2 repeatedly and write down each remainder, then read the remainders from bottom to top. 13 ÷ 2 = 6 r1, 6 ÷ 2 = 3 r0, 3 ÷ 2 = 1 r1, 1 ÷ 2 = 0 r1, so 13 is 1101.
How do I convert hex to decimal?
Each hex digit is a power of 16, with A–F meaning 10–15. FF = 15×16 + 15 = 255, and DEADBEEF = 3,735,928,559. Every group of 4 binary digits is exactly one hex digit, which is why programmers use hex.
What is two’s complement?
It’s how computers store negative integers: invert all the bits of the positive number and add 1. In 8 bits, −5 is 11111011 (hex FB). Pick 8, 16, 32 or 64 bits to see the pattern and how the same bits read as signed or unsigned.
Is there a size limit?
No practical one: numbers are handled with arbitrary-precision BigInt, so 64-bit, 128-bit and larger values convert exactly, up to 4,000 digits.
How do I convert text to binary?
Open the Text tab and type. Each character becomes its UTF-8 bytes: “Hi” is 01001000 01101001. Accented letters and emoji use 2 to 4 bytes. Paste binary or hex bytes into the right-hand box to decode them back to text.