What is the difference between Lite and Strong mode?

Lite re-saves the PDF, strips metadata, and removes unused objects. Text stays selectable, savings are usually modest (5–30%). Strong renders each page to an image at the DPI you pick and rebuilds the PDF from those images — savings can be 70–90% for scanned/image-heavy PDFs, but text is no longer selectable.

What DPI should I pick in Strong mode?

100–120 DPI is fine for on-screen reading. 150 DPI is a good middle ground. 200+ DPI matches print quality but gives back much of the size savings.

Are my PDFs uploaded to a server?

No. Compression runs entirely in your browser using pdf-lib and pdf.js. The file bytes never leave your device.

Why did my PDF get larger?

If the original is already optimized, re-saving can add a few KB of overhead. Strong mode at very high DPI can also exceed the original. Try a lower DPI or stick with Lite for already-optimized files.

PDF Compressor

Reduce PDF file size locally in your browser. Pick Lite mode to keep text selectable, or Strong mode to rasterise pages for maximum savings.

Runs in browser
No signup
No tracking

PDF

drop or click

Drop a PDF here, or click to choose
Runs locally — files never uploaded

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How to use PDF Compressor

Drop a PDF or click to choose one.
Pick Lite to keep text selectable, or Strong for maximum size reduction.
If Strong, pick DPI and JPG quality.
Click Compress — the result downloads when ready.

When to use it

Shrinking a scanned contract under an email size limit.
Uploading a portfolio PDF to a job portal that caps attachments at 5 MB.
Preparing a document for a slow mobile connection.
Reducing the size of a multi-page invoice before archiving.

What it fixes

Online compressors that upload private documents to a server.
Desktop tools that watermark the output or charge per file.
Manually printing to PDF at a lower quality from the OS print dialog.

About PDF Compressor

PDF size matters when emailing contracts, uploading evidence to a portal with a strict cap, or attaching documents to a chat. Most online compressors upload your file to their servers, which is unacceptable for anything confidential.

This tool runs entirely in your browser. Lite mode uses pdf-lib to strip metadata and dead objects — text stays selectable, savings are modest. Strong mode renders every page through pdf.js to an image at the DPI you pick, then rebuilds the PDF from those rasterised pages. Strong is dramatic on image-heavy and scanned PDFs, where 70–90% reductions are typical.

References: pdf-lib — JavaScript PDF manipulation · Mozilla pdf.js — PDF renderer

Frequently asked

What is the difference between Lite and Strong mode?
Lite re-saves the PDF, strips metadata, and removes unused objects. Text stays selectable, savings are usually modest (5–30%). Strong renders each page to an image at the DPI you pick and rebuilds the PDF from those images — savings can be 70–90% for scanned/image-heavy PDFs, but text is no longer selectable.
What DPI should I pick in Strong mode?
100–120 DPI is fine for on-screen reading. 150 DPI is a good middle ground. 200+ DPI matches print quality but gives back much of the size savings.
Are my PDFs uploaded to a server?
No. Compression runs entirely in your browser using pdf-lib and pdf.js. The file bytes never leave your device.
Why did my PDF get larger?
If the original is already optimized, re-saving can add a few KB of overhead. Strong mode at very high DPI can also exceed the original. Try a lower DPI or stick with Lite for already-optimized files.

Discussion

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