Base64 Encoder / Decoder
Convert text and files to and from Base64 instantly — pick standard or URL-safe variants, preview image data URIs and copy or download in one click. Free and private.
What is the Base64 Encoder / Decoder?
Base64 is an encoding that represents arbitrary bytes using a 64-character alphabet, so binary data can travel through text-only channels like JSON, URLs, emails or HTML. Toollyz Base64 Encoder/Decoder converts both ways — UTF-8 aware text in or out — and also handles whole files: drop any file in and get its Base64 plus a ready-to-paste data URI; if it's an image, you'll see a live preview rendered from that data URI. You can switch between standard Base64 and URL-safe Base64 (`base64url`, using `-` and `_` with no padding — the variant used by JWT, OAuth and many APIs). Decoding catches malformed input and shows the exact error. Files are read in your browser; nothing is uploaded.
How to use it
- Pick the Text or File tab.
- For text, choose Encode or Decode and pick Standard or URL-safe Base64.
- Type or paste your input — the result appears instantly in the output box.
- For files, drop one in to get the Base64 and a copy-ready data URI (with image preview when applicable).
Benefits
- Instant, live conversion as you type (UTF-8 aware).
- Standard or URL-safe (base64url) variants with one click.
- File mode for any file — text, JSON, image, PDF — directly in the browser.
- Image data-URI preview rendered from the encoded Base64.
- Download decoded Base64 back to a binary file.
- Clear error message when Base64 input is malformed.
- Swap input and output to chain conversions.
- 100% private — files and text never leave your browser.
Frequently asked questions
What is Base64?
Base64 is a way of encoding any byte sequence as text using 64 printable characters (A–Z, a–z, 0–9, +, /). It's used wherever binary data has to travel through text — JSON, JWTs, email attachments, HTML data URIs.
What's the difference between Base64 and Base64URL?
Standard Base64 uses + and / and may end with =. URL-safe Base64 (base64url) replaces + with - and / with _ and drops the = padding, so the string is safe to put in URLs and JWTs. Pick whichever your downstream consumer expects.
Why is the encoded output longer than my input?
Base64 needs 4 characters to represent every 3 bytes, so output is roughly 4/3 the size of input — about 33% larger. The tool shows the exact byte delta so you can plan around it.
Is Base64 encryption?
No. Base64 is just a way to represent bytes as text — anyone can decode it instantly. Use it for transport, not for hiding secrets. If you need privacy, encrypt the data first (e.g. with our Secure Notes tool).
Why did decoding fail?
Standard Base64 accepts only A–Z, a–z, 0–9, +, /, =. A space, a stray hyphen or a missing character will throw. The tool surfaces the engine's exact error so you can fix it.
Can I encode files like images and PDFs?
Yes. Switch to the File tab and drop any file in — you'll get its Base64 plus a ready-to-paste data URI. For images, a live preview confirms it round-trips correctly.
What's a data URI?
A data URI like `data:image/png;base64,…` lets you embed a file directly into HTML, CSS or JSON without a separate request. The tool prepares one with the correct MIME type for any file you drop in.
Does it work with Unicode and emoji?
Yes — text is UTF-8 encoded before Base64 encoding (and decoded back from UTF-8), so accented characters, emoji and non-Latin scripts round-trip correctly.
Is my data sent anywhere?
No. Toollyz has no server — all encoding and decoding happens in your browser. The file mode reads files locally and discards them when you leave the page.
Is this Base64 tool free?
Completely free with no signup and no limits. Encode or decode as much text or as many files as you like, privately in your browser.