Base64 to PDF Converter

Paste a Base64 string (or a data:application/pdf;base64 URI), preview the PDF inline, and download it. Everything runs in your browser — nothing is uploaded.

How to convert Base64 to a PDF

Paste the Base64 into the input box above — it works with or without the data:application/pdf;base64, prefix. Click Preview PDF to decode the string and render it in the inline viewer, then click Download PDF to save it as document.pdf. URL-safe Base64 (using - and _) and missing = padding are both handled automatically, so you don't need to clean up the string first.

Why won't my PDF open?

If the preview is blank or the download won't open, it's almost always one of these:

Truncated Base64: the string was cut off when it was copied, so the PDF is incomplete. Re-copy the full value.
Not actually a PDF: a valid PDF starts with the bytes %PDF. This tool checks for that signature and warns you when it's missing.
Extra whitespace or quotes: pasting a value straight out of JSON often drags in quotation marks, escaped newlines, or \n sequences. Strip those down to the raw Base64 payload.

Note: very large PDFs decode fine — there's no size limit on the decoding itself. The inline preview, though, depends on your browser's built-in PDF viewer; if a browser can't render PDFs inline you can still use Download PDF and open the file in a desktop reader.

Is this private?

Yes. The conversion is fully client-side. The Base64 is decoded into a Blob in your browser and the preview uses a local object URL (blob:) — the document is never uploaded to any server. That matters for confidential files like contracts, invoices, or signed certificates: they stay entirely on your machine. You can confirm it in DevTools → Network: decoding a PDF fires no upload request.

Frequently asked questions

How do I convert Base64 to a PDF?

Paste the Base64 into the box above — with or without the data:application/pdf;base64, prefix — and click Preview PDF. The tool decodes the Base64 into bytes locally, wraps them in a Blob, and renders the document. Click Download PDF to save it as document.pdf.

Why does my decoded PDF fail to open?

Usually truncated or partial Base64, data that isn't really a PDF (a valid PDF starts with %PDF), or stray whitespace and quotes pasted in from JSON. This page flags input that doesn't begin with %PDF so you can catch a bad paste quickly.

Is it safe to decode confidential PDFs here?

Yes — decoding runs entirely in your browser. The Base64 becomes a Blob locally and the preview uses a local object URL, so nothing is uploaded. Confidential documents never leave your device.

Can I decode a data URI directly?

Yes. Paste a full data:application/pdf;base64,JVBERi0... URI and the prefix is stripped automatically. Raw Base64 and URL-safe Base64 with missing padding work too.

Encode a file to Base64?

The main base64.dev tool's File mode turns any PDF or document into a Base64 string.

Open base64.dev →