Base 16 · live nibble view
Hex Converter
Hexadecimal to decimal, binary, octal and text as you type — with the four bits behind every digit.
—
—
—
—
—
A hex converter that shows its working
Most converters hand you a number and stop. This one also breaks your input into bytes and nibbles, so you can see why the answer is the answer. That matters when you are staring at a memory dump, a color code or a protocol field and the number alone is not the thing you needed to understand.
Type into the box above and every output updates on the keystroke. Nothing is sent to a server, there is no convert button to hunt for, and the tool sits at the top of the page where a tool belongs.
What a hex converter does
Hexadecimal is base 16. Instead of ten digits it has sixteen: 0 to 9,
then A through F standing in for ten to fifteen. Converting between hex
and another base changes the notation, not the value. FF and 255 are the
same quantity written two ways, exactly as "twelve" and "XII" are.
Because the engine uses arbitrary-precision arithmetic, long values — hashes, 128-bit identifiers, whole memory addresses — convert exactly, with no rounding and no silent overflow above 253.
How to use it
- Pick what your input is using the chips above the box. The default is hex; switch to decimal, binary, octal or plain text if that is what you are pasting.
- Paste or type your value. Separators are tolerated — spaces, commas, colons in a MAC address, hyphens in a UUID, a leading
0xor#are all stripped. - Read whichever output you came for and press Copy. The nibble view under the input shows the bit pattern behind each digit if you want to check the arithmetic yourself.
The nibble view
Four bits is called a nibble, and it is the reason hexadecimal exists. One hex digit holds exactly one nibble — no remainder, no carrying between digits — so a byte is always two hex digits and a 32-bit register is always eight. No other common base lines up with binary that cleanly, which is why hex became the shorthand engineers write bit patterns in.
Because the mapping is digit-by-digit, you can convert hex to binary by hand faster than hex to decimal. 3F is 0011 then 1111, read straight off the table. Decimal offers no such shortcut, because 10 is not a power of 2.
Every hex tool on this site
Number conversion
Moving a value between base 16 and base 10, 2 or 8. Hex to decimal, decimal to hex, hex to binary, binary to hex, hex to octal and octal to hex.
Text and encoding
Treating hex digits as bytes and bytes as characters. Hex to ASCII, ASCII to hex, hex to text, text to hex, hex to Base64 and Base64 to hex.
Color
Hex as a way of writing three color channels. Hex color, hex to RGB, RGB to hex, hex to HSL, HSL to hex, a color picker and a color chart.
Arithmetic and reference
A hex calculator for all four operations, plus reference tables and guides to the number system itself.
Hexadecimal digit reference
Sixteen rows worth memorising. Everything else in hex is built from them, and the full hexadecimal table extends this to every value a byte can hold.
| Hex | Decimal | Binary | Octal |
|---|---|---|---|
| 0 | 0 | 0000 | 0 |
| 1 | 1 | 0001 | 1 |
| 2 | 2 | 0010 | 2 |
| 3 | 3 | 0011 | 3 |
| 4 | 4 | 0100 | 4 |
| 5 | 5 | 0101 | 5 |
| 6 | 6 | 0110 | 6 |
| 7 | 7 | 0111 | 7 |
| 8 | 8 | 1000 | 10 |
| 9 | 9 | 1001 | 11 |
| A | 10 | 1010 | 12 |
| B | 11 | 1011 | 13 |
| C | 12 | 1100 | 14 |
| D | 13 | 1101 | 15 |
| E | 14 | 1110 | 16 |
| F | 15 | 1111 | 17 |
| Hex | Decimal | Why you see it |
|---|---|---|
| 0F | 15 | Low nibble mask |
| 10 | 16 | First two-digit hex value |
| 20 | 32 | Space character in ASCII |
| 41 | 65 | Capital A in ASCII |
| 7F | 127 | Top of the ASCII range |
| 80 | 128 | Sign bit of a single byte |
| FF | 255 | A byte with every bit set |
| 100 | 256 | One byte overflowed |
| FFFF | 65,535 | Largest 16-bit unsigned value |
| FFFFFFFF | 4,294,967,295 | Largest 32-bit unsigned value |
What is hexadecimal?
Hexadecimal is a positional numeral system with a base of sixteen. Positional means a digit's
place decides its weight: in 2A7 the 2 is worth 2 × 256,
the A is worth 10 × 16 and the 7 is worth 7. Add them
and you get 679.
It survives because computers store everything in bits, and bits in groups of four map onto hex
digits perfectly. A color like #1A73E8 is three bytes. A MAC address is six. A
SHA-256 hash is thirty-two. Writing any of those in binary would be unreadable, and in decimal
would hide the byte boundaries entirely. There is more on this in
our guide to hexadecimal.
Frequently asked questions
Is this hex converter free?
Yes. There is no account, no usage limit and no paid tier. The conversion runs in JavaScript in your own browser, so it costs nothing to serve.
Does my data get uploaded anywhere?
No. The page contains the whole converter. Whatever you type stays on your device, which matters if you are pasting keys, hashes or anything else sensitive.
Can it handle very large hex values?
Yes. The engine uses arbitrary-precision integers, so a 256-bit hash or a 128-bit UUID converts exactly. There is no 64-bit ceiling and no floating-point rounding.
Do I need to type the 0x prefix?
No, and it does no harm if you do. A leading 0x, #, $ or backslash-x is recognised and removed, as are spaces, commas, colons and hyphens.
Does hex care about upper and lower case?
Not for the value. 0xff and 0xFF are identical numbers. Case matters only where a specification or a string comparison demands a particular style.
Why does hex use letters?
Base 16 needs sixteen symbols and decimal supplies only ten, so A through F were borrowed for ten through fifteen. The choice is conventional, not mathematical.