What is Base64 Encoding?
Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format using 64 printable characters. It's widely used to safely transmit binary content through text-only channels like JSON APIs, XML documents, email bodies, or HTML data attributes without corruption.
ToolsMatic performs Base64 encoding entirely inside your browser using the FileReader API. No file is ever uploaded to any server, making it ideal for encoding confidential PDFs, private documents, or sensitive business content.
How to Convert PDF to Base64 on ToolsMatic
- Step 1 — Upload your PDF: Drag and drop your PDF onto the upload area or click to browse. Files up to 50MB are supported for browser compatibility.
- Step 2 — Configure output: Choose whether to include the Data URI prefix (for direct HTML embedding) and enable RFC-compliant line break formatting.
- Step 3 — Convert: Click "Convert to Base64". The encoded string appears in the preview panel with character count and size information.
- Step 4 — Copy or download: Copy the Base64 string to your clipboard with one click, or download it as a .txt file for later use.
Raw Base64 vs Data URI Format
Raw Base64
Just the encoded string with no prefix. Use this format when embedding the value in JSON payloads, API requests, or database fields where you control the context.
JVBERi0xLjQKJeLjz9MKMyAwIG9iago8PC9UeXBlL1BhZ2UvUGFyZW50IDIgMCBSL1Jlc291cmNlczw8L0ZvbnQ8PC9GMSAxIDAgUj4+Pj4vTWVkaWFCb3hbMCAwIDYxMiA3OTJdL0NvbnRlbnRzIDQgMCBSPj4KZW5kb2JqCjQgMCBvYmoKPDwvTGVuZ3RoIDQ0Pj4Kc3RyZWFtCkJUCi9GMSAxMiBUZgoxMDAgNzAwIFRkCihIZWxsbyBXb3JsZCkgVGoKRVQKZW5kc3RyZWFtCmVuZG9iago=
Data URI Format
Adds the prefix data:application/pdf;base64, to
the encoded string. Use this format for direct embedding in
HTML <iframe src>, <object data>,
or CSS url() attributes.
data:application/pdf;base64,JVBERi0xLjQKJeLjz9MKMyAwIG9iago8PC9UeXBlL1BhZ2UvUGFyZW50IDIgMCBSL1Jlc291cmNlczw8L0ZvbnQ8PC9GMSAxIDAgUj4+Pj4vTWVkaWFCb3hbMCAwIDYxMiA3OTJdL0NvbnRlbnRzIDQgMCBSPj4KZW5kb2JqCjQgMCBvYmoKPDwvTGVuZ3RoIDQ0Pj4Kc3RyZWFtCkJUCi9GMSAxMiBUZgoxMDAgNzAwIFRkCihIZWxsbyBXb3JsZCkgVGoKRVQKZW5kc3RyZWFtCmVuZG9iago=
Why is Base64 Output Larger?
Base64 encoding increases file size by approximately 33% because it represents every 3 bytes of binary data as 4 ASCII characters. This overhead is the necessary trade-off for ensuring binary content survives transmission through text-only channels that might otherwise corrupt raw binary data.
For example, a 1 MB PDF becomes approximately 1.33 MB when Base64 encoded. The preview panel shows both sizes so you can plan accordingly for storage or transmission limits.
Common Use Cases for PDF to Base64
- API Integration: Embed PDFs in JSON request/response bodies for REST APIs that don't support multipart uploads.
- Email Embedding: Include PDF attachments directly in email HTML bodies using Data URI format.
- Database Storage: Store PDFs as text fields in databases that don't support BLOB types.
- Frontend Embedding: Display PDFs inline in web pages using iframe src with Data URI.
- Configuration Files: Include small PDFs in YAML, JSON, or XML config files for application bundling.
ToolsMatic vs Other Base64 Tools
| Feature | ToolsMatic | Base64Encoder.org | Online-Convert | CloudConvert |
|---|---|---|---|---|
| No file upload | ✅ | ❌ | ❌ | ❌ |
| Privacy first | ✅ | ❌ | ❌ | ❌ |
| Data URI option | ✅ | ⚠ Manual | ❌ | ⚠ Paid |
| Line break formatting | ✅ | ❌ | ❌ | ❌ |
| One-click copy | ✅ | ✅ | ⚠ Select manually | ❌ |
| Download as .txt | ✅ | ⚠ Copy paste | ❌ | ❌ |
| Size comparison | ✅ | ❌ | ❌ | ❌ |
| Free with no limits | ✅ | ⚠ Ads | ⚠ Daily limits | ⚠ Credits |
| 50MB file support | ✅ | ⚠ ~10MB | ⚠ ~25MB | ✅ |
| Zero console errors | ✅ | ⚠ Mixed | ⚠ Mixed | ⚠ Mixed |
PDF to Base64: Frequently Asked Questions
Base64 encoding is used to safely transmit binary data through text-only channels. Common uses include embedding files in JSON APIs, email attachments, HTML data attributes, or database text fields where raw binary might be corrupted.
Data URI format adds a prefix that tells browsers the content type and encoding. This allows you to use the string directly in HTML src attributes, CSS url() values, or JavaScript without additional configuration.
RFC 2045 recommends limiting Base64 lines to 76 characters for compatibility with email and legacy systems. Enable this option if your destination system requires formatted output; disable for compact storage.
Copy the Base64 string and paste it into your JSON
payload, API request body, or HTML attribute. For
example: {"pdf": "JVBERi0xLjQK..."} or
<iframe src="data:application/pdf;base64,JVBERi0xLjQK...">.
Never. All Base64 encoding happens entirely inside your browser using the FileReader API. Your PDF never leaves your device and is never transmitted to any server at any point.
Files up to 50MB are supported for Base64 conversion in modern browsers. Larger files may cause memory issues or timeouts. For very large PDFs, consider server-side conversion tools or chunked processing.
Password-protected PDFs must be unlocked first. Use our free Unlock PDF tool to remove the password, then return here to encode the PDF to Base64.
Use your programming language's Base64 decode function.
In JavaScript: atob(base64String) or
Buffer.from(base64, 'base64') in Node.js.
Save the decoded binary as a .pdf file. Many online
tools also offer Base64 to PDF conversion.