Direction
Paste base64
Result
LocalThis runs in your browser. Nothing you paste is sent anywhere.
Base64 · Local tool
Base64 decode and encode
Decode base64 to text, or encode text to base64, without leaving the page.
01 / Your device
the file stays here
02 / Browser memory
the work runs locally
03 / Your downloads
the result arrives here
How it works / no cloud
A conversion engine, not an upload form.
The conversion happens in JavaScript on the page as you type. There is no request to make: base64 is a text transformation, and a server would only add a round trip and a copy of your data on someone else's disk.
- Offline ready
- Installable app
- No file limit queue
Straight answers
No accordion. Nothing hidden.
- Is it free?
- Yes, with no watermark and no page limit.
- Does it need an account?
- No. There is no account system.
- Is my file processed on my device?
- Yes. The file is read by your browser and never uploaded. There is no server to send it to.
- What formats are supported?
- Text in either direction. Accepts line breaks, missing padding, the URL-safe alphabet, and a data: URL prefix. Output can be copied or downloaded as .txt.
- What are the limits?
- Bounded by what your browser will hold in a text box, which in practice is several megabytes. Base64 that decodes to a file rather than text is offered as a download instead.
- Does it work on mobile?
- Yes, on any modern mobile browser. Large files are limited by the memory the phone gives the browser.
- Does it work offline?
- Yes, once the page has loaded. The tool keeps working with no network connection.
- Why does my accented or non-English text come back wrong elsewhere?
- Because most quick base64 tools, and the browser's own atob and btoa, work on latin1 rather than UTF-8. Anything outside the first 256 characters gets mangled, and emoji break outright. This tool encodes and decodes through UTF-8, so text goes in and comes back identical.
- Can I paste a whole data: URL?
- Yes. A prefix like data:image/png;base64, is stripped before decoding, so you can paste what you copied out of CSS or HTML without trimming it first.
- What if it decodes to a file rather than text?
- You get told, and offered the bytes as a download. Showing them as text would produce a screen of replacement characters that looks like a broken decode, so the tool checks whether the result is valid UTF-8 before claiming it is text.
- Is base64 encryption?
- No, and it is worth being clear about. Base64 is an encoding, not a cipher. Anyone can decode it in one step, exactly as you are doing here. It hides nothing.
Keep working locally
3 available · more coming