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PDF File Size Analyzer

Drop a PDF to see what is making it large, which stored objects dominate, and which pages deserve attention before you compress.

Local PDF analysis · nothing uploaded

See what is making your PDF large

Drop a PDF and get a fast size breakdown, the largest stored objects, page-complexity hot spots, and practical optimization priorities before you compress anything.

Images & fontsStored object bytesPage hot spotsOptimization prioritiesCSV & JSON

Drop a PDF here or choose a file · up to 150 MB

Ready. Analysis stays in this browser tab.

File size—

Pages—

Average / page—

Largest size driver—

Where the stored bytes are

Direct byte evidence from the PDF object spans plus unattributed PDF syntax.

Best optimization moves

Evidence first — no generic “compress everything” advice.

Largest stored objects

Useful for spotting a single giant image, font program, attachment, or stream.

Object	Type	Stored size	Image / filter

Page hot spots

Complexity evidence — not fake per-page byte attribution for shared resources.

Page	Image draws	Fonts	Operators	Geometry

Document signals

Compress PDF

Accuracy note: total file bytes and matched object spans are measured locally. Shared resources can serve multiple pages, so page rows show complexity hot spots rather than pretending each page has an exact stored-byte cost.

Advanced PDF structure & object diagnostics

Local PDF evidence · structure · optimization priorities

PDF Size & Structure Diagnostic Studio

Find out why a PDF is large without uploading it. Combine byte-level object-span evidence with PDF.js page complexity, metadata, images, fonts, attachments, incremental-revision signals and practical optimization priorities.

Raw object-span byte auditImages · fonts · streams · attachmentsPage complexity, not fake page bytesIncremental revisions · linearizationCSV · JSON · Print · local history

Choose the PDF you actually need to diagnose

No PDF selected.

Local memory cap: 150 MB. The file stays in this browser tab.

Ready. No PDF has been read.

File size—

Pages—

Object spans—

Attributed coverage—

Image objects—

Font evidence—

Attachments—

Revision markers—

PDF version—

Fast Web View—

Encryption marker—

1 · Where the raw object bytes appear

Bucket	Object-span bytes	Share of file

Residual bytes include PDF syntax outside matched indirect objects and any structures the best-effort scanner cannot safely attribute.

2 · Largest raw objects

Object	Class	Stored span	Filter	Image pixels

3 · Optimization priority ladder

Analyze a file to generate evidence-based priorities.

4 · Document metadata

5 · Export & repeat use

Page complexity — without pretending it equals page byte size

Shared images and fonts can serve multiple pages, so assigning exact stored bytes to each page is often misleading. This table instead reports page dimensions, image paint operations, unique font references, extracted text items, annotations and PDF.js operator count.

Page	Geometry	Image draws	Font refs	Text items	Annotations	Operators

How to turn the audit into a smaller PDF

Images first when evidence says images

Downsample oversized scans/photos and choose an appropriate image codec. Do not rasterize clean vector/text pages merely because a compressor offers the option.

Fonts are a portability tradeoff

Embedded fonts preserve appearance. Prefer sensible subsetting/reuse over blindly unembedding fonts when the PDF must render consistently.

Incremental saves can preserve old revisions

Multiple EOF/startxref markers can indicate incremental updates. A clean rewrite may remove obsolete revisions, but signed PDFs need special care.

Fast Web View is not compression

Linearization reorganizes data for progressive loading. It can improve web delivery while leaving total file size similar or even slightly larger.

Truth boundary: raw indirect-object spans are measured directly from the selected file, but category attribution is best-effort. Compressed object streams, shared resources, binary content and unusual PDFs can limit classification. PDF.js page complexity is not exact page byte cost. This page diagnoses; it does not modify the PDF, guarantee compression savings, validate every low-level PDF rule, or replace Acrobat Preflight / dedicated forensic parsers for compliance work.

Core Before exporting the PDFs

Use a focused flagship page for the six highest-demand PDF jobs; specialist PDF tools remain available from the full hub.

All 44 PDF tools

Merge PDFCombine multiple PDFs Split PDFExtract ranges or separate pages Compress PDFReduce PDF file size PDF to JPGTurn PDF pages into images JPG to PDFTurn images into one PDF Organize PDFReorder, rotate or delete pages

Why total file size is not enough

A 100-page text PDF can be smaller than one scanned page. The useful question is which embedded resources and document structures are consuming storage.

Separate exact measurements from estimates

The selected file size and matched object spans are measured in local bytes. Classification is evidence-based, while page complexity intentionally avoids claiming a fake per-page byte total for shared resources.

Use object evidence to choose the next action

Image-heavy files point toward downsampling or recompression. Font-heavy files deserve subset/reuse review. Embedded attachments and repeated incremental revisions can add invisible weight. Linearization concerns delivery order, not guaranteed size reduction.

Keep the original private

The PDF is analyzed in this browser. Exported CSV/JSON reports contain diagnostic evidence; local history stores only numeric summaries and never stores the PDF bytes.

Know when this is not enough

Use a professional preflight/forensic tool when you need standards compliance, signature validation, exact low-level object-stream decoding, print-production certification or legal evidence. This Studio is a practical size diagnostic, not a compliance certificate.