Best PDF compression tools: a reproducible test

Run a fair comparison

Prepare three synthetic inputs: a text CV, a scanned letter and an image-heavy brochure. Keep their originals.
Run each candidate with documented quality settings. Record browser, device, version, elapsed time and output bytes.
Open each output in a separate reader. Compare fine text, images, page order, selectable text and links.
Score privacy and account friction separately from visual quality. A smaller file that loses required features is not a successful result.

A CONCRETE EXAMPLE

A situation to try.

Use the same three files for every candidate. A results row should contain input bytes, output bytes, time, text retained, links retained and visible defects. Leave untested cells empty.

Use the tool’s synthetic example first where available. The example here explains a decision; it is not a reported benchmark result.

Before you call it done.

Look at small type and thin lines at 200% zoom.
Try text extraction, search and link clicks.
Record settings that produce larger outputs too.

Know the limits.

Comparative benchmark results are still pending. IndiaDigital is not declared the best compressor.

This tool’s current boundary: Lossless reserialization only in this build. Image recompression is not available. Already optimized files may not shrink.

MEASURED, NOT ASSUMED · 2026-10-05

Our lossless compression check.

Three synthetic PDFs were processed through the actual compression adapter. PDF.js independently read and rendered all five input/output pages. Extracted text and rendered pixels matched at scale 1 in this Windows/Node test.

Internal fixture results — not a competitor ranking
Fixture	Input bytes	Output bytes	Saved	Text layer
cv	1,823	1,167	35.98%	Retained
scan	8,670	8,241	4.95%	Absent before and after
brochure	27,538	25,871	6.05%	Retained

The source fixtures used uncompressed object streams. These reductions do not predict results for already-optimized files. Forms, signatures, attachments, accessibility and browser/mobile performance were not certified by this check.

Download and reproduce the evidence

Versions, method and SHA-256 hashes (JSON) · Raw results (CSV)

Reproduction: run npm test -- tests/tool-evidence.test.ts in the project checkout. The downloadable report records the environment. Timing is a single Node adapter run, not a browser speed score.

Evidence and scope

Technical source guidance and task-specific output checks. These do not establish that every file, browser or device passes.

Use the checks above on your own exported result. A source explains the format or mechanism; it is not proof that this export preserved every feature.

Technical reference: PDF-LIB: page operations and exports ↗

How we verify outputs · Device compatibility