Compress PDF
Reduce the file size of a PDF — strong compression for scans, or a light re-pack that keeps text selectable.
Strong mode turns each page into a compressed image. Text in the result can no longer be selected or searched.
Basic mode re-packs the PDF without changing its content. Savings are usually small (0–20%).
Runs in your browser — your data never leaves your device.
About the Compress PDF
Many online forms, job portals and email services limit file size — often to 1 MB or 2 MB. Compress PDF helps you get under that limit without installing any software.
Strong mode is best for scanned documents and PDFs made from photos: each page is redrawn as an optimised image, which usually gives large savings. Basic mode re-packs the PDF's internal structure without touching its content, so text stays selectable and searchable — savings are smaller.
If the compressed file would not be smaller than the original, the tool tells you instead of giving you a bigger file.
How to use the Compress PDF
- Choose or drop one PDF file.
- Pick Strong (scans, photos) or Basic (text documents).
- In Strong mode, choose the image quality — Balanced suits most uses.
- Click Compress PDF. The original and new sizes are shown before the download starts.
How it works
Strong: each page is rendered with the open-source pdf.js library at the chosen resolution (96, 120 or 150 DPI), saved as a JPEG image and placed on a page of exactly the same size in a new PDF built with pdf-lib.
Basic: the document is re-saved with compressed object streams, which removes some overhead.
Saving % = (original size − new size) ÷ original size × 100.
Examples
- A 6.8 MB scanned admission form (4 pages) → about 0.9 MB in Strong / Balanced mode, small enough for a 2 MB upload limit.
- A 1.2 MB text-only report in Basic mode → around 1.0–1.1 MB, with all text still selectable.
Frequently asked questions
Is my PDF uploaded to your server?
No. The PDF is opened and processed by your own browser. It never leaves your device, so it is safe to use with private documents.
Why can I no longer select text after strong compression?
Strong mode turns each page into an image. That is what makes scans much smaller. Use Basic mode if you need selectable text.
Which quality should I choose?
Balanced (120 DPI) is clear on screen and fine for printing forms. Choose Smallest for the tightest size limits, or Better quality for documents with small print.
Why did the size not go down?
Some PDFs are already well optimised. If the result would be larger, the tool keeps your original and tells you. Try Strong mode or a lower quality.