Compress PDF Free Online

Upload your PDF and get a smaller file in seconds. Text, fonts and vector graphics stay perfectly sharp — images are optimised for screen viewing. See exact before-and-after savings for every file. No account needed, files deleted immediately after download.

or drag & drop your PDF files here
Up to 3 files  •  15 MB total  •  Free forever
No files stored
Done in seconds
No watermarks

What This PDF Compressor Does

This compressor reduces the file size of your PDF documents using Ghostscript, a trusted open-source PDF engine used in enterprise and government environments worldwide. It resamples embedded raster images to 72 DPI for screen-optimised output, applies efficient compression to image streams, subsets embedded fonts to include only the characters actually used in the document, and removes unreferenced internal objects — producing a clean, smaller PDF without any change to text, layout or vector content.

After every compression, Convixy shows you the exact original size, the compressed size and the percentage saved per file — so you always know precisely what changed. If Ghostscript would produce a larger file than your original (which can happen with already-optimised PDFs or text-heavy files with very little image content), the tool detects this automatically, discards the bloated output, and serves your original file unchanged with a clear "Already optimised" notice rather than quietly returning a larger file.

Pass email attachment limits

Gmail and Outlook cap attachments at 25 MB. Compressing first means no more "file too large" rejections.

Meet portal upload limits

Government forms, HR systems and procurement platforms commonly enforce 5–10 MB file size caps.

Faster loading on mobile

A 1 MB PDF opens instantly on a mobile connection. A 15 MB PDF can take thirty seconds or more.

Efficient long-term storage

Smaller files cost less to store and back up, and transfer faster between systems and devices.

Tips for the Best Compression Results

Frequently Asked Questions

Is this PDF compressor completely free?

Yes, completely free with no hidden conditions. There are no compression limits, no watermarks added to your output, and no account or payment information required at any stage. You can compress as many files as you need, as often as you need, without any cap on daily or monthly usage. Convixy's tools are funded by advertising, not by paywalls or per-compression fees.

The only constraints are technical ones: a maximum of three files per upload session and a combined total upload size of 15 MB. Most PDFs requiring compression fall well within these limits — the tool is specifically useful for the large files that are difficult to share, and most of those are between 2 MB and 15 MB.

How much will my file shrink?

The reduction depends entirely on what the PDF contains. Files with many high-resolution photographs or scanned pages at 300 DPI or higher typically see the most dramatic savings — often 60% to 85% smaller. A scanned 20 MB document can compress to under 2 MB with no visible difference in text readability at normal viewing sizes. Exported presentations from PowerPoint or Keynote embed full-resolution background images and compress dramatically. Marketing materials and brochures with rich photography also respond very well.

PDFs consisting mostly of text and simple vector graphics typically see 10% to 30% reduction, since there is less high-resolution raster content to resample. After every compression, Convixy displays the exact original size, the new compressed size and the percentage saved — so you always know precisely what changed rather than having to guess whether the tool made a difference.

Will compression affect the quality of my document?

Text, vector graphics, fonts and the document's structural layout are completely unaffected and remain perfectly sharp at any zoom level — this is because they are not raster content and are not touched by the image resampling step. Images are resampled to 72 DPI, which is the standard resolution for on-screen digital viewing and is more than sufficient for contracts, reports, invoices, presentations, correspondence and the vast majority of business documents.

The one scenario where it is worth checking the output carefully is a PDF containing photographs specifically intended for large-format professional printing at high DPI — for example, a printed brochure or exhibition material where fine image detail at physical print size genuinely matters. For all everyday digital uses — viewing on screen, attaching to email, uploading to portals, sharing in messaging apps — the visual difference between the original and the compressed version is imperceptible at normal viewing distances and sizes.

What technology powers the compression?

Compression is handled by Ghostscript, an open-source PostScript and PDF interpreter that has been maintained since 1988 and is widely deployed in enterprise, government and publishing environments. Files are processed with the -dPDFSETTINGS=/screen profile and -dCompatibilityLevel=1.4 flag, which instructs Ghostscript to resample raster images to 72 DPI, apply efficient JPEG compression to image streams, subset embedded fonts to only the characters actually used in the document, remove unreferenced internal data objects, and write a clean PDF 1.4-compatible output.

The process is completely lossless for all text and vector content — only raster image data is resampled. After compression, Convixy compares the output file size to your original. If the compressed version would be larger (which can happen when a PDF contains very little image content and the overhead of reprocessing outweighs any savings), the original is served instead with an "Already optimised" notice, ensuring you always receive the smaller of the two files.

Can I compress multiple PDF files at once?

Yes — up to 3 files at a time, with a combined total size of 15 MB across all files in the session. When you compress two or three files together, all results are bundled automatically into a single ZIP download for convenience. Individual download links and a per-file size summary are shown below the main button so you can see exactly what was saved for each individual file and download any specific one without the archive.

To select multiple files, hold Ctrl (Windows) or Command (Mac) while clicking files in the file picker, or drag all the files together onto the upload area. If you need to compress more than three files, download the first batch and then upload the next set — there is no cooldown period between sessions.

What happens if my PDF is already optimised?

When Ghostscript's output would be larger than your original — which happens with already-optimised PDFs, PDFs that are almost entirely plain text with very few images, or PDFs that were previously compressed with a similar tool — Convixy detects this automatically by comparing file sizes after processing. It discards the larger output and serves your original file unchanged.

You will see a blue "Already optimised" notice instead of a size-reduction summary, so you always know exactly what happened rather than receiving a file that is mysteriously the same size or, worse, larger than what you uploaded. This detection runs on every file individually, so in a batch of three files you might see two with reductions and one "Already optimised" notice — each file is handled independently based on its own content.

Can I compress a password-protected PDF?

PDFs that require a password to open cannot be processed, because the compression engine needs full read access to the document's content stream to resample images and subset fonts. If you upload a password-protected file, the compression will fail and an error message will explain the reason. The fix is to remove the password protection in your original PDF software — Adobe Acrobat, Preview on macOS, or any PDF editor — then upload the unlocked file here.

PDFs with owner-level restrictions — which limit printing, copying or editing but do not require a password to open — can usually be compressed without any issue, since the compression engine only needs read access to process the content, not permission to edit it. If you are unsure whether your PDF requires an open password, try opening it in a PDF viewer: if it opens without asking for a password, it should compress successfully.

What types of PDF compress best?

The largest reductions come from PDFs with substantial embedded raster image content. Scanned documents at 300 DPI or higher can exceed 20 MB for just a few pages; compression routinely brings these under 2 MB with no visible difference in text readability at normal screen viewing sizes. Exported presentations from PowerPoint or Keynote embed full-resolution slide background images and photographs and compress dramatically — a 15 MB presentation PDF often compresses to under 3 MB. Marketing materials and brochures with rich photography, product catalogues, and design portfolios also respond very well.

Text-only PDFs — contracts, legal documents, technical specifications, spreadsheet exports — compress less, typically 10–30%, since there is minimal raster image content to resample. They still benefit from font subsetting (removing unused glyph data from embedded fonts) and structural overhead removal. PDFs generated programmatically from code — for instance, invoices produced by accounting software — are often already well-optimised and may return "Already optimised" results, which is expected and correct behaviour.

Are my files private and secure?

Yes. All file transfers happen over an encrypted HTTPS connection, so your document is protected in transit. Once your compressed PDF is ready and downloaded, both the uploaded original and the compressed output are automatically deleted from Convixy's servers — typically within the same browsing session and always within one hour of upload. No manual deletion is required on your part.

We do not read, index, analyse, share or retain the content of your documents under any circumstances. No account is required, so there is no user profile for your files to be associated with, and no email address or personal information is collected. This tool is safe to use with confidential contracts, financial statements, medical documents, legal filings and any other sensitive content.

What can I do with the PDF after compressing?

Once you have a smaller PDF, Convixy has a full suite of tools to manage it further. To combine multiple compressed files into a single document — for instance, merging a compressed report with a compressed cover letter — use Merge PDF. To extract only the pages you need from a larger document, use Split PDF. If you need to go back and adjust the source document before compressing again, Word to PDF, Excel to PDF and PowerPoint to PDF all convert the original files cleanly with no watermarks.

For the smallest possible final PDF, the recommended workflow is: convert your Office file to PDF using the relevant converter, then compress the resulting PDF here. This sequence consistently produces smaller files than compressing a PDF that was generated by other means, because the initial conversion from Office format already produces a reasonably lean PDF structure for Ghostscript to work with.