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Base64 File Converters: PDF, ZIP, Audio, Video

Convert files to Base64 for JSON, APIs and email, or turn a Base64 string back into the PDF, archive, document, audio, video or font it holds, with a preview before you save.

Free no sign-up, no limits Local nothing uploaded Updated Oct 27, 2026
PDFBase64 to PDFView and save PDFs FILEFile to Base64Any file, several at once, any size FILEBase64 to fileDetect the format, preview, download PDFPDF to Base64Embed PDFs in JSON, APIs and email MP3Base64 audio playerPlay and save Base64 audio MP3Base64 to MP3Play and save MP3 MP3Audio to Base64MP3, WAV, OGG, M4A to Base64 MP3MP3 to Base64MP3 as data URI or raw Base64 ZIPBase64 to ZIPList files and save the archive ZIPZIP to Base64Archives as Base64 strings WAVWAV to Base64Uncompressed audio as Base64 WAVBase64 to WAVPlay and save WAV MP4Video to Base64MP4, WebM, MOV to Base64 MP4Base64 to videoPlay and save video MP4MP4 to Base64MP4 clips as Base64 MP4Base64 to MP4Play and save MP4 DOCXBase64 to WordRead the text, save the .docx DOCXWord to Base64DOCX files as Base64 XLSXBase64 to ExcelPreview the sheet, save the .xlsx XLSXExcel to Base64Spreadsheets as Base64 PPTXBase64 to PowerPointSlide text preview, save the .pptx TTFFont to Base64TTF, OTF, WOFF2 as @font-face TTFBase64 to fontPreview and save fonts

Which file tool do I need

Your taskTool
Any file to Base64, several at onceFile to Base64
Base64 of unknown type back to a fileBase64 to file
PDFs for APIs, e-signature services and emailPDF to Base64, Base64 to PDF
ArchivesZIP to Base64, Base64 to ZIP (lists the files inside)
Word, Excel, PowerPointWord to Base64, Base64 to Word, Excel to Base64, Base64 to Excel, Base64 to PowerPoint
Audio from a speech or TTS APIBase64 audio player, Base64 to MP3, Base64 to WAV
Audio to Base64Audio to Base64, MP3 to Base64, WAV to Base64
VideoVideo to Base64, MP4 to Base64, Base64 to video, Base64 to MP4
Web fonts in CSSFont to Base64 (writes the @font-face rule), Base64 to font

The decoders preview what the browser can show: PDFs in the browser’s PDF viewer, audio and video with a player, fonts with sample text, the file list of a ZIP, the text of a DOCX, the first sheet of an XLSX and the slide text of a PPTX. Each one also shows the SHA-256 of the decoded bytes, so you can compare it with a checksum from the sender.

Recognizing a file from its first characters

Base64 starts withFile type
JVBERi0PDF (%PDF-)
UEsDBAZIP, and every ZIP-based format: DOCX, XLSX, PPTX, ODT, EPUB, JAR, APK
SUQzMP3 with an ID3 tag
//s to //vMP3 frame without an ID3 tag (FF FB)
UklGRRIFF: WAV audio, or a WebP image
T2dnUwOgg (Vorbis or Opus audio)
AAAAGGZ0eXA, AAAAIGZ0eXAMP4, M4A, MOV (ftyp box)
GkXfoWebM or Matroska
d09GMg, d09GRgWOFF2, WOFF
AAEAAA, T1RUTwTrueType, OpenType font
H4sIgzip, handled by the gzip decoder

A Base64 string that begins with none of these may still be a file in a less common format, or text. Base64 to file tries the full list of signatures, and if the bytes turn out to be text it shows that instead.

Practical notes

  • APIs and JSON: most services expect plain Base64 without a data: prefix and without line breaks. The encoders default to that; switch the output to a data URI only for browsers and HTML.
  • Email attachments are Base64 wrapped at 76 characters. To read the attachments of a raw message, use the email decoder.
  • Mismatched types: a decoder page for one format still saves other formats, and it warns when the content does not match. A “PDF” that starts UEsDBA is a ZIP.
  • Big files: encoding works in chunks, and the text preview is shortened above 4 MB. Download always saves the complete result; very large output can only be saved, not copied.

For pictures, the image tools add resizing and format conversion, and the text tools cover strings and charsets.

FAQ

How do I convert Base64 to a file when I do not know the type?

Paste it into Base64 to file. It reads the first bytes, names the format (PDF, ZIP, PNG, MP3 and many more), shows a preview where the browser can and suggests the right extension for the download.

Is there a size limit for files?

There is no upload, so the limit is your device’s memory. Large files are encoded in chunks; above roughly 48 MB the Base64 can no longer be copied to the clipboard and is saved as a .txt file instead.

Why is my Base64 file a third larger than the original?

Base64 stores 3 bytes in 4 characters, so the encoded size is about 133% of the file, plus line breaks if the output is wrapped. The size calculator gives the exact length for any file size.