Will compressing lose quality?

You choose. Best quality changes no picture at all. The other options re-save the photographs inside the PDF at a lower resolution, which is where the saving comes from, and PDFCheetah shows the size each one reaches before you run it.

Why is my file barely smaller?

Because the saving comes from the pictures inside a PDF, and yours has little to gain. A text-heavy or form-heavy file barely changes; a picture-heavy one shrinks most. Where nothing can be saved, your original is kept.

Will my text still be selectable?

Yes, on every option but one. Text and vector artwork are never rebuilt — only pictures are re-saved. The exception is Flatten to images, which turns each page into a picture: it is never chosen for you, and it is labeled where you pick it.

No; it is made smaller in your browser.

Compress PDF Online Free — Reduce PDF File Size, No Upload

Processed on this device

Selecting and processing files stays in this browser.

Checking offline readiness

Offline availability is confirmed after this tool loads.

Why there is no daily limit, and no upload

How to compress a PDF

Open the PDF you want to make smaller.
PDFCheetah checks what is inside it on this device and offers the sizes it can reach.
Choose the size you want, then select Make this PDF smaller.
Select Download to save the smaller PDF.

Where the saving comes from

PDFCheetah finds the pictures inside your PDF, works out how large each one is actually drawn on the page, and re-saves the oversized ones at a resolution that suits how they are used. Everything else is left exactly as it was — text stays selectable and searchable, vector artwork stays sharp at any zoom, and links and form fields keep working. The one exception is Flatten to images, which turns each page into a picture: it is only ever a choice you make, and is never selected for you. The work happens on this device.

What is left alone

Pictures already the right size for the page keep every pixel they have, but they are still re-saved at the quality you chose — and kept only if that comes out smaller. Left exactly as they were: anything not stored as a JPEG, plus JPEG 2000 and JBIG2 images, spot colors, black-and-white scans, and pictures that carry transparency. CMYK pictures are re-saved as screen colors, so check a file headed for a printing press. A PDF protected with a password is refused rather than processed, because opening it would need the password you have not been asked for.

Why some PDFs barely get smaller

A text-heavy PDF carrying large embedded fonts will barely change. Shrinking those means rebuilding the fonts, and PDFCheetah does not do that yet: done badly, it destroys a document’s searchable text. When the smaller copy is not actually smaller, PDFCheetah keeps your original and tells you so instead of handing you a bigger file. If you are trying to get under an email attachment limit, that limit belongs to the mail servers at both ends rather than to PDFCheetah, so find the number you have to beat and compare the estimated sizes here against it.

Common questions

Will compressing lose quality?: You choose. Best quality changes no picture at all. The other options re-save the photographs inside the PDF at a lower resolution, which is where the saving comes from, and PDFCheetah shows the size each one reaches before you run it.
Why is my file barely smaller?: Because the saving comes from the pictures inside a PDF, and yours has little to gain. A text-heavy or form-heavy file barely changes; a picture-heavy one shrinks most. Where nothing can be saved, your original is kept.
Will my text still be selectable?: Yes, on every option but one. Text and vector artwork are never rebuilt — only pictures are re-saved. The exception is Flatten to images, which turns each page into a picture: it is never chosen for you, and it is labeled where you pick it.
Is my file uploaded?: No; it is made smaller in your browser.