🔐 Base64 Encoder / Decoder
Encode & decode text or files with Base64, fast, local, secure. Nothing leaves your browser.
🖼️ Image Preview
How to use this tool
Overview
Free Base64 Encoder & Decoder is a free online utility for encoding and decoding text or files to and from Base64 format, right in your browser. As a 100% client-side developer tool, nothing you enter ever reaches a server. Your data stays private and secure on your device. Base64 encoding is widely used in web development for embedding binary data into data URIs, transmitting data in APIs, storing images or fonts in CSS, and handling raw binary content over text-based protocols. Our tool supports converting plain text to Base64 strings, decoding Base64 strings back to readable text, encoding image files (PNG, JPG, GIF) into Base64 data URIs, and decoding Base64 strings back to viewable images, all with a single click. Simply paste your text or Base64 string, select encode or decode mode, and the result appears instantly. Developers use it for API payload testing, creating inline images, and debugging encoded data. No downloads, no sign-up, no data collection. Just a fast, private Base64 codec that works on any device including phones, tablets, and desktops.What Base64 actually does
Base64 converts arbitrary bytes into 64 printable ASCII characters so binary data can travel through text-only channels: JSON payloads, email headers, data URIs and configuration files. The encoding inflates size by about 33%, which is normal and expected. It is a transport format, not compression. Decoding reverses the mapping and restores the original bytes exactly. This tool handles both directions, plus image-to-data-URI and data-URI-to-image conversion, using the browser's native UTF-8 aware encoder so accented characters and emoji survive the round trip.
Processing details and limits
| Property | Base64 tool behavior |
|---|---|
| Modes | Text to Base64, Base64 to text, image to data URI, data URI to image |
| Character support | Full UTF-8, including accents and emoji |
| Size overhead | ~33% larger than the original binary (expected) |
| Image input | PNG, JPG, GIF and other browser-readable formats |
| Processing | 100% client-side JavaScript, no upload |
| Network requests | None after the page loads |
| Cost | Free, no account, no request quota |
Privacy: encoded data never leaves the browser
Base64 strings often carry API tokens, credentials or customer data, and decoding them on a third-party server would defeat the point of encoding. Everything here runs locally: nothing is transmitted, stored or logged, and the page works offline after the first load. Verify it in the Network tab, encoding and decoding produce no traffic.
Practical tips
- Never treat Base64 as encryption. It is reversible by anyone.
- Strip the data URI prefix before decoding raw Base64 image data.
- Use data URIs sparingly in CSS: large images bloat the stylesheet.
- Expect invalid-character errors when the string was truncated in transit.
- For files, prefer multipart uploads over Base64 in JSON when possible.
Related: browse the developer tools for JSON formatting, hashing, JWT decoding and more.
Frequently asked questions
What is Base64 encoding? +
Base64 is a method of converting binary data into a text string using 64 ASCII characters. It is commonly used for embedding images in HTML, sending attachments via email, and storing binary data in text formats.
Can I encode and decode files, not just text? +
Yes. Upload any file, images, documents, or binary data, and the tool encodes it to Base64. You can also paste Base64 to decode it back to the original file.
Is there a character or file size limit? +
There is no artificial limit. Large files produce longer Base64 strings, but the tool handles them in the browser without issues.
What is the difference between Base64 encoding and encryption? +
Base64 encoding is NOT encryption. It is a reversible representation format. Anyone can decode Base64. It provides no security.