Skip to main content
ToolNimbly

PDF Compressor

Two modes, two honest trade-offs — and a plain statement of how many bytes you actually saved.

Runs in your browser. Nothing you enter here is uploaded to a server.

Loading the tool…

Embed the PDF Compressor

Paste this into any page. The tool runs in place, and the credit line below it links back here.

Appearance

Adjust height if your layout needs it.

Please keep the “Powered by” line. It is the only thing we ask in return, and it is what keeps the tool free to embed.

What this tool does

PDF compression is oversold almost everywhere. What is actually possible in a browser is either rewriting the document structure, which is safe but often saves very little, or rasterising the pages into images, which saves a lot but destroys selectable text, links, form fields and accessibility structure. This tool offers both, defaults to the safe one, and compares the before and after byte counts rather than declaring success because a process finished.

How to use this tool

  1. Step 1: Add a PDF

    One file, up to 100 MB and 500 pages. Password-protected files are detected and refused.

  2. Step 2: Choose a mode

    Optimise structure keeps the pages exactly as they are and removes unnecessary metadata and objects. Rasterise pages converts each page into a compressed image.

  3. Step 3: Set the quality if you rasterise

    Resolution and JPEG quality control the trade-off. The warning about what rasterising discards is displayed before you proceed, not after.

  4. Step 4: Compare and decide

    The result shows both sizes and the actual change. If the output is larger, the tool says so and recommends keeping the original.

Worked example

A 14 MB scanned contract in both modes

Twelve pages scanned at high resolution, already stored as embedded images.

Optimise structure
about 13.7 MB — a 2% saving
Rasterise at 150 DPI
about 2.4 MB — an 83% saving
What rasterising cost
Any selectable text layer, bookmarks and links
Page count and size
Unchanged in both modes

For a scan that was already images, rasterising costs little and saves a great deal. For a text document produced by a word processor, the same operation would destroy the text layer for a much smaller gain.

What each mode does

Structure optimisation rewrites the document without touching page content. Rasterisation renders each page to an image and builds a new PDF from those images.

  • Structure optimisation removes document metadata and unused objects and rewrites the cross-reference table. Vectors, text and fonts are all preserved.
  • Most of a typical PDF is embedded images and fonts. Structure optimisation cannot touch either, which is why its savings are usually in the low single digits.
  • Rasterisation renders at your chosen resolution and re-encodes as JPEG. Everything that was not a visible pixel is gone: text, links, annotations, form fields and tagged structure.
  • Page count and physical page dimensions are preserved in both modes, and the result is re-parsed after generation to confirm it is a valid, renderable PDF.

Sources and methodology

ToolNimbly performs this work locally in your browser using the method shown above. Read how ToolNimbly tests calculations and generated documents.

Structural optimisation versus raster compression

A PDF is a container, so there is no single compression method that helps every document. Structural optimisation removes redundant objects and rewrites streams without changing the visible pages. It is safe for selectable text and vectors but may save little when the source is already optimised. Raster compression renders pages as images, which can save far more on scans and image-heavy documents.

The trade-off is substantial: rasterisation can remove selectable text, links, form fields, annotations, layers and digital signatures. A signed document may become visually similar but cryptographically invalid after any rewrite. Resolution and JPEG quality determine whether small print remains readable. Test a few representative pages before processing an important archive, keep the original, and use a dedicated archival or document-management workflow when legal authenticity, accessibility or searchable text must be preserved.

Limitations and privacy

What this tool does not do

  • Structure optimisation frequently saves almost nothing. That is an honest outcome, and it will be reported as such rather than dressed up.
  • Rasterising destroys selectable text, links, bookmarks, annotations, form fields and accessibility tagging. This is irreversible in the output file.
  • Rasterising a text-based PDF often makes the file larger, not smaller, because a page of crisp text compresses far better as text than as an image.
  • Image recompression inside an otherwise intact PDF is not available in this version — that is a middle option requiring tooling the browser does not provide.
  • Password-protected PDFs are refused. Maximum 100 MB and 500 pages.

The document is parsed, rewritten and re-checked entirely in your browser. No bytes are transmitted, and the original file on your device is never modified.

Frequently asked questions

Why did my PDF barely get smaller?

Because most of its size is embedded images and fonts, and structure optimisation cannot compress those. If the document is a scan, the rasterise mode will help substantially. If it is text, it was probably already efficient.

Will compressing ruin my document?

Structure optimisation will not — pages come through untouched. Rasterising will change the document fundamentally: it becomes a series of pictures, and text, links and form fields are lost. The tool warns you before you choose it.

Which mode should I use?

Start with structure optimisation, since it is safe. If the saving is not enough and the document is a scan or something you only need to view and print, try rasterising and check the result before you discard the original.

Can you compress a PDF without losing quality at all?

Only to the extent that the file contains waste to remove, which is usually not much. Any large reduction involves discarding something — resolution, colour depth, or the text layer. Anyone promising both is not being straight with you.

What if the compressed file is bigger?

The tool tells you plainly and recommends the original. This happens most often when rasterising a text-based PDF, where images of text take more space than the text itself.

Read more about this

Related tools

Other tools people use alongside the pdf compressor.

  • Merge PDF Files

    Combine up to ten PDFs into one document in any order you like. Pages are copied, not re-rendered, so text stays selectable and page sizes stay exact.

  • Split PDF Files

    Extract pages, split every page into its own file, cut a PDF into ranges or delete pages you do not need. Page sizes and rotation are preserved.

  • Image Compressor

    Compress JPG, PNG and WebP images in your browser. Adjust quality, cap dimensions and download one file or a ZIP. Nothing is uploaded to a server.

  • PDF to JPG Converter

    Render any page of a PDF to a JPG image at your chosen resolution. Pick pages or ranges, preview thumbnails and download single files or a ZIP.

Part of PDF Tools. Last reviewed .