Standard Base64 uses + and / characters, which are special characters in URLs. URL-safe Base64 replaces these with - and _ so the string can be used in URLs and HTTP headers without percent-encoding.
Free Developer Tool
Base64 Encoder & Decoder
Encode text or files to Base64, decode Base64 back to text or downloadable files, and preview Base64 image data URIs — all processed locally in your browser.
- ✔ Text encode & decode
- ✔ File to Base64
- ✔ Base64 to file
- ✔ Image preview
- ✔ URL-safe variant
- ✔ Free Forever
Encode and Decode Base64 in Seconds
Base64 is the standard encoding for transmitting binary data over text-only channels — used constantly in API authentication headers, JWT tokens, email attachments, CSS data URIs, and configuration files. This free tool handles all four common Base64 tasks: encoding and decoding text, converting any file to a Base64 string, decoding a Base64 string back to a downloadable file, and previewing Base64-encoded images directly.
How It Works
1. Choose a Tab
Text, file encoding, file decoding, or image preview.
2. Paste or Upload
Paste text or Base64, or drag and drop any file.
3. Encode or Decode
Click the button and see the result instantly.
4. Copy or Download
Copy to clipboard or download the result as a file.
Drop any file — image, PDF, ZIP, binary — to get its Base64-encoded string.
Use the "Include data URI prefix" option to get a ready-to-use
data:mime/type;base64,... string for CSS or HTML.
Click to upload or drag and drop any file
Any file type, up to ~10 MB recommended
Paste a Base64 string (with or without a data URI prefix) to decode it back
to a downloadable file.
Paste a Base64-encoded image (with or without the data URI prefix) to preview it
and get the correct
<img> or CSS background-image snippet.
Base64 Basics
When Is Base64 Used?
API Authentication
HTTP Basic Auth credentials are Base64-encoded in the Authorization header on every request.
JWT Tokens
The header and payload sections of every JSON Web Token are Base64URL-encoded strings.
Data URIs
Inline images in CSS and HTML use Base64 data URIs to embed image bytes directly in the file.
Email Attachments
MIME email attachments are Base64-encoded so binary files can travel over text-based protocols.
FAQsBase64 Encoder & Decoder
What is the difference between standard Base64 and URL-safe Base64?
Why does Base64 make files larger?
Base64 encodes every 3 bytes of binary data as 4 ASCII characters, resulting in approximately 33% overhead compared to the original binary size.
Is my data uploaded anywhere?
No. All encoding and decoding happens entirely in your browser using JavaScript. Nothing is sent to any server.