PDF to Base64
Use this free PDF to Base64 converter to turn any Portable Document Format document into a Base64 string or a ready-made code snippet. Select a local .pdf file (or paste a link to a remote one), pick the output format and press Encode PDF to Base64.
How to convert PDF to Base64 online
- Choose Local file and select a .pdf file, or choose Remote URL and paste a link.
- Select the output format: plain Base64, data URI, HTML tag, CSS, JavaScript, JSON or XML.
- Click Encode PDF to Base64. The result appears instantly with a preview.
- Copy the result to the clipboard or download it as a .txt file.
About PDF (Portable Document Format)
PDF, created by Adobe in 1993 and standardised as ISO 32000, describes a fixed-layout document with text, fonts, vector graphics and images that looks the same on every device.
APIs often send PDFs (invoices, labels, reports) as Base64 strings inside JSON. Every PDF encoded to Base64 begins with "JVBERi0", the encoded form of the "%PDF-" header.
| Developed | 1993, Adobe (ISO 32000) |
|---|---|
| Type | Fixed-layout document |
| Can contain | Text, fonts, images, forms |
| Browser support | Built-in viewer in all browsers |
| File signature | 25 50 44 46 ("%PDF") |
Output formats
Choose how the result should be wrapped. The converter can return:
- txt: only the Base64 string, ready to paste into code, a database field or an API request.
- uri: a complete
data:URI that you can paste in a browser address bar or use anywhere a URL is accepted. - html embed: an
<embed>tag. - html object: an
<object>tag with a type attribute. - html iframe: an
<iframe>that renders the content inline. - html hyperlink: an
<a>link that downloads or opens the embedded file. - javascript popup: JavaScript that opens the content in a new window.
- json: a JSON object with the file name, MIME type and data.
- xml: an XML element with the data inside a CDATA section.
Is it safe and how large will the result be?
Your file is never uploaded: it is read and converted locally by your browser using the File API, so even confidential documents stay on your device.
Base64 represents every 3 bytes with 4 characters, so the encoded result is about 33% larger than the original file (plus a few bytes for padding and the data URI prefix).
Frequently asked questions
How do I convert PDF to Base64?
Select your .pdf file above and click "Encode PDF to Base64". The converter reads the file in your browser and outputs the Base64 string or a ready data URI.
What does a Base64-encoded PDF start with?
A PDF file encoded to Base64 typically starts with "JVBERi0". As a data URI it begins with "data:application/pdf;base64,".
Is there a file size limit?
There is no hard limit because the conversion runs locally, but very large files produce very long strings. Files up to about 50 MB work comfortably in modern browsers.
How do I convert the Base64 back to PDF?
Use the Base64 to PDF decoder: paste the string, and you can preview and download the original .pdf file.
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