Convert Hex to Binary

Each hex digit maps directly to 4 binary bits – no arithmetic needed. 0 = 0000, 9 = 1001, A = 1010, F = 1111. The tool walks your hex input character by character and concatenates the matching 4-bit patterns. So FF becomes 1111 + 1111 = 11111111.

Because in most real-world uses of hex (memory addresses, network packets, register values, ASCII bytes), the bit width carries meaning. A hex byte is 8 bits – even if its numeric value is small. 0x0A as a byte is 00001010, not 1010. Stripping zeros gives the integer value but loses the size context. Use it only when you want pure number semantics, not byte semantics.

None emits one long continuous bit string. Nibble (4 bits) groups as 0000 1010 (matches hex digit boundaries). Byte (8 bits) groups as 00001010 11111111 (standard for byte-oriented protocols). Word (16 bits) and Dword (32 bits) match common CPU register widths. The underlying bits are identical – only the visual spacing and left-padding change.

Practically unlimited. The algorithm is O(n) in hex length and uses plain strings – no `Number` or `BigInt` arithmetic is performed (each hex digit just looks up its 4-bit pattern in a table). 1 MB of hex input (2 million bits of output) finishes in under 50 ms on a modern laptop.

Bare hex digits (FF), with 0x/0X prefix (0xFF), space-separated (FF 00), underscore-separated (FF_00 or DE_AD_BE_EF), or any mix. Case is irrelevant – aB and AB and Ab all decode identically.

It still works – each hex digit is 4 bits regardless of whether the total is a multiple of 2 (nibble) or 8 (byte). 0x1ABCD has 5 hex digits = 20 bits. With byte grouping on, the output left-pads to 24 bits so the groups align, but the underlying value is unchanged. There’s no “must be a whole number of bytes” restriction.

When each line of input is a separate hex value – maybe a column of register dumps from a debugger, or a list of IP addresses in hex, or a file offset table. Batch mode decodes each line independently. If one line has a typo, only that line fails (shown in the error list below the output); every other line still converts.

Not directly – hex-to-binary is a representation mapping, not arithmetic. If you want the binary of -5, you need two’s complement encoding (which requires a chosen bit width, usually 8/16/32/64 bits). Use our “decimal to two’s complement binary” tool for that. This tool treats all input as non-negative magnitudes.

No. All processing happens in your browser’s JavaScript engine – no network requests fire during conversion, and no server stores or logs your hex values. You can verify with your browser’s Network tab. The tool works offline after the initial page load.

Yes. The mapping is bijective for any multiple-of-4-bit binary string. Use our “binary to hex” converter (or any binary-to-hex tool) and you’ll recover the original hex exactly – assuming your binary input has a multiple of 4 bits (which it will if you got it from this tool). For non-4-divisible bit widths, the converter usually left-pads with zeros.