Base64 represents binary data (PDF, image, ZIP…) as ASCII text. It is common in APIs, email, and data URIs.

Can I convert any file type?

Yes. The converter is universal: PDF, DOCX, XLSX, images, audio, video, APK, EXE, JSON, CSV and more. The only hard limit is size (50 MB).

Are my files uploaded to a server?

No. Conversion runs only in your browser. Nothing is sent to Ontoom.

How do I go from Base64 back to a file?

Save the string in a .txt and use Base64 → file. The tool detects the type (PDF, DOCX, PNG…) and lets you download with the correct extension.

Is Base64 encryption?

No. Base64 only encodes; it is not encryption. Anyone with the string can decode the content.

Ontoom

Base64 Universal

Convert any file to Base64 and back — in your browser, with nothing uploaded to a server.

Rebuilds these and other formats

max 50.00 MB

PDF
DOCX
XLSX
PPTX
PNG
JPEG
WEBP
GIF
SVG
ZIP
MP3
MP4

Drop the .txt with Base64 here

Accepts .txt · .b64 · .base64 · max 50 MB

Important: Everything runs in the browser. Nothing is uploaded. Limit: 50 MB.

What is a universal Base64 converter?

It turns any file into Base64 text and rebuilds the file from that string. Useful for developers, QA and integrations that need Base64 payloads.

File to Base64 and Base64 to file

In File → Base64 you generate the string and can copy or download a .txt. In Base64 → file you upload the .txt and download the detected PDF, image or other format.

Which formats are supported?

Any file up to 50 MB. Examples: PDF, DOCX, XLSX, PPTX, PNG, JPEG, WEBP, GIF, SVG, ZIP, RAR, 7Z, MP3, MP4, APK, EXE, JSON, CSV, XML, HTML and many more.

How to use Base64 Universal

Open File → Base64 or Base64 → file.
Upload the file (or the .txt with Base64).
Copy the string, download the .txt, or download the reconstructed file.

Privacy in the browser

Like other Ontoom tools (for example JWT), processing is local — ideal for fixtures and tests without exposing sensitive data.

Frequently asked questions

What is Base64?: Base64 represents binary data (PDF, image, ZIP…) as ASCII text. It is common in APIs, email, and data URIs.
Can I convert any file type?: Yes. The converter is universal: PDF, DOCX, XLSX, images, audio, video, APK, EXE, JSON, CSV and more. The only hard limit is size (50 MB).
Are my files uploaded to a server?: No. Conversion runs only in your browser. Nothing is sent to Ontoom.
How do I go from Base64 back to a file?: Save the string in a .txt and use Base64 → file. The tool detects the type (PDF, DOCX, PNG…) and lets you download with the correct extension.
Is Base64 encryption?: No. Base64 only encodes; it is not encryption. Anyone with the string can decode the content.