PDF Size Analyzer

Runs in browser PDF Analysis & Repair

Breaks the file down by object type with counts and shares, lists the largest streams, measures how much a structural rewrite would save, and gives concrete advice — before you compress blindly.

Privacy: Processed locally in your browser. Your file is not uploaded.

What is inside a PDF file, and what does repairing one do?

A PDF is a header naming its version, a body of numbered objects (pages, fonts, images, streams), a cross-reference table that records where each object starts, and a trailer pointing at the catalogue and the metadata. Metadata lives in the Info dictionary (title, author, dates, producer) and, since PDF 1.4, in an XMP stream; fonts are embedded whole, subsetted or only referenced by name. A viewer that cannot find an object walks the file to rebuild the cross-reference table — repair does the same and writes the rebuilt table, which fixes most "damaged file" errors without touching the pages.

How to use PDF Size Analyzer

  1. Drop a PDF.
  2. Click "Analyze size".
  3. Read the breakdown and follow the advice (Compress PDF, Cleanup…).

PDF Size Analyzer features

  • Bytes by category: images, fonts, page content, XMP, embedded files, structure…
  • The 15 largest objects with type and page hints
  • Measured saving of a lossless rewrite
  • Concrete advice on what to do next
  • Read-only — the file is not modified
  • Local processing

PDF Size Analyzer example

Why is this 60 MB?

Input:

presentation.pdf

Output:

Images 52.1 MB (87%) · Fonts 3.4 MB · Page content 1.1 MB · structure 0.6 MB; largest: image 1 380 0 R 9.8 MB (page 4); advice: images dominate — compress with image recompression

Frequently asked questions about PDF Size Analyzer

What usually makes a PDF large?

Images — especially scans stored at 300–600 DPI in colour — followed by embedded fonts (several full fonts, or the same font embedded many times), then incremental updates that keep old versions of edited objects.

What is "structure & overhead"?

Bytes not inside any stream: object headers, dictionaries, cross-reference tables and whitespace. A rewrite with object streams reduces it.

Does the analysis change my file?

No. It only reads the file; the rewrite estimate is computed in memory and discarded.

Is my PDF uploaded to a server?

No. The file is opened and processed by your browser with WebAssembly and JavaScript; nothing is sent to Mutqan Soft or anyone else. Close the tab and the file is gone. Downloading the result needs a free account — no subscription, no payment.

Can I use it on a password-protected PDF?

Yes, if you know the password: the file list asks for it once and every operation then works on the decrypted pages. The output is saved without a password unless you protect it again.

Technical notes

Every stream object is classified by its dictionary (/Type, /Subtype, /Filter, font program keys, ICC and shading markers) and its encoded length summed. A dry re-save with object streams measures the structural saving without producing a file.

References