Free online PDF to PDF converter

People re-save a PDF when a receiving application rejects its PDF version, a file is too large to share, or an archival system requires PDF/A. The operation keeps the document in PDF but can rewrite its internal structure, compression, metadata, compatibility level, or supported features.

What the PDF format is

PDF, or Portable Document Format, stores fixed page geometry, text, fonts, vector graphics, raster images, annotations, forms, metadata, and sometimes embedded files in a device-independent document. Adobe Acrobat, Microsoft Word, LibreOffice, web browsers, scanners, desktop-publishing software, and reporting systems create PDF files.

PDF is used for invoices, scanned records, submitted forms, manuals, contracts, technical drawings, and documents that must retain their layout across operating systems and printers. Files with the same .pdf extension can use different PDF versions and standards, including PDF 1.4, PDF 1.7, and PDF/A profiles; viewers and other software may therefore support different features.

What the PDF format is good for

PDF preserves page appearance more reliably than editable office formats and can embed fonts for consistent display and printing. It supports selectable text, searchable scans after OCR, digital signatures, encryption, accessibility tags, annotations, interactive fields, hyperlinks, bookmarks, and attachments, although support varies by viewer and processing tool.

A PDF-to-PDF rewrite can reduce file size, change compatibility, produce a validated PDF/A archival copy, flatten forms or annotations, repair some structural problems, remove metadata, or add linearization for faster progressive web display. Depending on the settings, rewriting can remove or change JavaScript, embedded files, layers, transparency, accessibility tags, signatures, annotations, or editable form fields.

How to convert PDF to PDF

Using 101convert.com

1. Open the PDF-to-PDF converter on 101convert.com.
2. Choose option
3. Start the conversion and download the resulting PDF.

This option requires no installed software and is suitable for non-sensitive files. 

Using Adobe Acrobat

1. Open the source PDF in Adobe Acrobat.
2. For a basic rewritten copy, use File → Save As and choose a new filename.
3. For compression or detailed output control, use All tools → Optimize a PDF. Adjust image downsampling, JPEG quality, font removal, metadata, transparency, and other options, then save.
4. For PDF/A output in Acrobat Pro, open All tools → Use print production → Preflight, select a PDF/A conversion profile, run the fix, and save the result.
5. Reopen the output and check page count, text search, links, bookmarks, images, forms, annotations, attachments, and signatures.

Changing a filename from file.pdf to another PDF filename does not convert or normalize the file. PDF/A also requires validation against the selected profile; changing metadata or the extension alone is insufficient.

Using Ghostscript locally

Ghostscript rewrites pages through its pdfwrite device. This example creates a broadly compatible PDF with moderate image compression:

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dBATCH -sOutputFile=output.pdf input.pdf

On Windows, the executable is commonly gswin64c rather than gs. Use /screen for smaller, lower-resolution output, /ebook for moderate quality, and /printer for higher-resolution output. Omit -dPDFSETTINGS when preserving source quality matters more than reducing size. Ghostscript can flatten or discard interactive and specialized PDF features.

Using qpdf for structural changes

qpdf can rewrite and linearize a PDF without deliberately recompressing all page content:

qpdf --linearize input.pdf output.pdf

Use this for web-optimized output or structural normalization rather than aggressive compression. It does not repair every damaged PDF and does not remove encryption without the required password and authorization.

Quality and compatibility limits

A PDF-to-PDF rewrite is not automatically lossless. Downsampling and JPEG recompression reduce image detail, and converting a scanned PDF cannot create selectable text unless OCR is performed. Inspect output at high zoom or print it when typography, diagrams, barcodes, or signatures are exacting.

Any modification usually invalidates a digital signature because the signed byte sequence changes. Encrypted files may require the owner password, and permission settings can block editing or extraction. Test interactive forms, calculations, JavaScript, tagged accessibility structure, layers, embedded files, hyperlinks, bookmarks, annotations, and attachments after conversion.

Keep the original PDF. A rewritten copy may not retain every source feature, and a PDF/A conversion may intentionally remove encryption, scripts, audio, video, attachments, or other features that conflict with archival requirements.