Binary decoder.

Binary is the alphabet of two digits, 0 and 1, the bits a computer stores. Written out, a byte is eight digits: the letter A, 65, is 01000001. There is nothing to decode but the grouping, and nothing shorter: a binary string is eight times the size of the bytes it shows.

Every byte is written as its eight bits, most significant first, usually with a space between bytes so the groups can be read. The output is 700% larger than the input, eight digits for every byte. The decoder takes the digits with or without spaces, as long as there are eight per byte.

Learning how computers store text and numbers, reading a bit field or a flag byte, checking a protocol's bit layout, digital electronics homework, and showing a child what a letter looks like to a machine.

Technically, since it is only digits; practically no one sends a URL eight times longer than it needs to be.

It is the least efficient encoding by far and the only one that shows every bit. Use it to see or teach; use hex to read bytes at a glance and Base64 to carry them.

No. Binary is an encoding, not encryption: it changes how bytes are written, not who can read them, and anyone can decode it with no key. Encrypt first (AES, age, a library's sealed box) when the content needs protecting, then encode the ciphertext if it has to travel as text.

Paste the Binary and the text appears as you type; the status line says how many characters became how many bytes. Spaces and line breaks are ignored, so a wrapped value from an email or a config file pastes as it is. Press Swap to encode the result again.

The decoder gives you the bytes as UTF-8 text when they are text. When they aren't, an image or a PDF for instance, it still shows them, with replacement characters where the bytes aren't valid UTF-8, and the status line says so. Use Binary to file to download the bytes as they are instead.

Binary uses 0 and 1, and the error names the first character that isn't among them. Check for a stray quote, a trailing comma or a prefix from the surrounding code. Spaces and line breaks are dropped for you, and the count of digits has to be a multiple of eight.

Nothing leaves your browser. The text is read into memory on your machine and the encoding is computed there, in plain JavaScript; the page makes no request with it. Load the page, go offline and it keeps working.

No. The Binary decoder is free and opens without a sign-in, an account or an install.

Nothing. The Binary decoder holds your input in the page's memory, so closing or reloading the tab clears it, and it saves nothing in this browser.

It takes 0 and 1 only, eight digits to a byte, with spaces ignored. Anything else stops with a message naming the first character it can't read.

Yes: drop a text file that holds the Binary on the input. The file is read as text and decoded, so a saved encoding doesn't need pasting.

Press Swap once there is a result and the same tool becomes the Binary encoder, with the decoded text moved into the input.

Closest to the Binary decoder: Binary encoder, Binary to file, File to Binary, Hex decoder. Each opens on its own page, free and in the browser.

The Binary decoder is one of 32 in its group. The group's page, /tools/encoding, lists them all.

The tool is free. Its interface is built from shadcn.io's own components (Button, Input, Slider and the rest of the registry under /ui), which come in React, Vue, Svelte and Solid. Pro adds the blocks and templates for the product around it.