Base64 to PDF

Paste the Base64 string or data URI into the box — the PDF is decoded, verified, and previewed automatically, with a Download button to save it.

You'll get a clear error explaining the decoded data doesn't have a valid PDF header, rather than a blank preview or a silent failure — this is the single most common real-world Base64-to-PDF problem, and it's checked directly rather than assumed.

Yes — Base64 has a second, URL-safe variant (using - and _ instead of + and /, usually with padding left off) that JWTs and many APIs actually produce. It's normalized automatically before decoding, so you can paste either variant directly.

Yes — it renders directly in the page using your browser's own built-in PDF viewer, the same one that opens a PDF link normally, so you can check it's the right document before saving anything.

No — decoding and verification happen entirely in your browser. Nothing you paste is sent to a server.

The most common causes: incorrect or missing padding, an invalid character outside the Base64 alphabet, or the data genuinely isn't PDF data at all (check the specific error message — it distinguishes "not valid Base64" from "valid Base64 but not a PDF"). Standard vs. URL-safe charset differences are handled automatically, so that specific mismatch shouldn't be the cause.

No artificial limit — very large Base64 strings just take a little longer to decode, since it all happens in your browser's own memory.

Yes — our PDF to Base64 tool does the reverse direction, with several output formats (Data URI, plain Base64, ready-made HTML) depending on where you need to use it.

Base64 encodes data in groups of 3 bytes to 4 characters. When the original file's length isn't an exact multiple of 3, one or two = padding characters get added at the end to keep that grouping intact — it's not meaningful data, just a legacy alignment marker. This tool accepts Base64 with or without it, since a lot of real-world sources (JWTs especially) omit it.

Standard Base64 only uses A–Z, a–z, 0–9, +, /, and = for padding; the URL-safe variant swaps in - and _ instead. Anything else — stray whitespace, line breaks, or other symbols — makes the string invalid. If your paste includes extra characters, this tool's error message will say the data failed to decode rather than silently producing a corrupted file.

No — Base64 is encoding, not encryption or hashing (it's not related to SHA-256, despite the two sometimes being confused). It's a public, fully reversible transformation with no secret key, so decoding requires no password — which is exactly what this tool does. If a PDF you received this way was meant to be confidential, treat it the same as an unencrypted attachment, not a protected one.

Python: open("file.pdf", "wb").write(base64.b64decode(b64_string)). PHP: file_put_contents("file.pdf", base64_decode($b64String)). PowerShell: [IO.File]::WriteAllBytes("file.pdf", [Convert]::FromBase64String($b64String)). All three decode the exact same way this tool does — they just write straight to a file on disk instead of showing an in-browser preview first.

Yes — completely free, no sign-up, no limits. Base64 itself is also just a public, open algorithm, not a paid format, so there's never a cost to decoding it anywhere.

The main ones: the encoded form is about 33% bigger than the original file, which is why the string you're pasting here is noticeably longer than the PDF it represents; and it provides zero security by itself — it's reversible by anyone, with no password or key involved, so it should never be treated as a way to protect sensitive data. Those trade-offs are the reason Base64 is used for transport (getting binary data through text-only channels), not for storage or confidentiality.

No — different jobs. UTF-8 encodes text; Base64 encodes arbitrary binary data (like a PDF's raw bytes, which aren't text at all) into printable characters. The one place they connect: Base64's output only ever uses plain ASCII characters, so it's automatically valid UTF-8 too — which is why a Base64-encoded PDF can be safely embedded in a JSON string or HTML page without extra escaping.