Compress PDF Document Online

What PDF compression means

PDF compression reduces file size by removing redundant data and optimizing images or fonts. It is not the same as converting formats or editing content.

How local PDF compression runs in the browser

Toolsly processes PDFs inside your browser using WebAssembly. The original file stays on your device throughout. No data leaves for a server.

A typical workflow starts with selecting a PDF. The tool reads the file structure, identifies compressible elements like images at 300 DPI, and rewrites streams with better algorithms such as Flate or DCT. Output appears as a new file ready for download.

Concrete inputs and outputs

Users supply a PDF with known traits. One example is a 12-page report containing four color photos. Original size measures 4.8 MB. After compression the file drops to 1.9 MB while keeping 150 DPI images.

Another case involves a 28-page scanned contract. Input size reaches 9.2 MB due to 200 DPI grayscale pages. Output lands at 3.1 MB with no loss of text readability.

A third example uses a 5-page invoice set with embedded logos. Starting at 2.4 MB, the result measures 780 KB.

Real workflow examples

In accounting teams, monthly expense reports move from email attachments to shared drives after compression. A 15-page ledger originally 6.7 MB becomes 2.3 MB.

Legal offices handle discovery bundles. A 42-page exhibit set shrinks from 11 MB to 4.8 MB before secure transfer.

Marketing departments prepare client decks. A 9-page presentation file falls from 3.9 MB to 1.4 MB for faster loading on mobile devices.

Format comparison for PDF assets

Element	Before size	After size	Pages affected	\ Notes
Scanned contract	9.2 MB	3.1 MB	28	200 DPI grayscale
Expense report	6.7 MB	2.3 MB	15	Color charts
Invoice set	2.4 MB	780 KB	5	Embedded logos
Client deck	3.9 MB	1.4 MB	9	Image heavy
Research paper	4.8 MB	1.9 MB	12	150 DPI photos
Tax filing	7.5 MB	2.8 MB	22	Mixed text and tables

Where PDF compression fits daily tasks

Combine compressed PDFs with other document utilities. Start by turning images into a single PDF at /images-to-pdf, then reduce the result. Merge several files first via /pdf-combine before shrinking the combined output.

Extract pages from large PDFs at /pdf-to-images when only select sections need compression. Convert Markdown notes to PDF at /md-to-pdf and compress the generated file. Convert Word files at /docx-to-pdf then apply size reduction.

Where to start

Try the document tools at /category/document for your first PDF.

FAQ

What file size reduction can I expect on a 10 MB scanned PDF? Expect 60 to 75 percent smaller output when images drop from 300 DPI to 150 DPI and unused metadata is stripped.

Does compression change text searchability inside the PDF? No. Text layers remain intact when only image streams are re-encoded.

Can I compress a PDF that already contains form fields? Yes. Form data and annotations stay preserved during the local rewrite step.

How does local processing handle password-protected PDFs? The browser must first unlock the file with the known password before compression begins.

Is there a limit on the number of pages processed at once? Browser memory sets the practical limit around 100 pages for typical consumer devices.