Compress PDF files without uploading them
Reduce PDF file size for email and uploads. Compression happens locally in your browser, so your documents never leave your device.
Drop your PDF files here
or choose a file — everything is compressed on your device
Files are not uploaded or stored. No signup required.
Private PDF compression, by design
Your files stay on your device
There is no upload step. The PDF is read, compressed and saved without ever leaving your browser.
No queue, no waiting room
Compression starts the moment you press the button, because nothing has to travel to a server first.
Free, with no account
No signup, no subscription and no watermark. Advertising keeps the tool free to use.
Works on any modern browser
Nothing to install on Chrome, Edge, Firefox or Safari, on both desktop and mobile.
Basic, Balanced and Heavy Compression
Every level re-encodes the images inside your PDF at a different resolution and quality. Text and vector artwork are preserved wherever it is technically possible.
Basic Compression
Images downsampled to roughly 200 DPI, re-encoded at high JPEG quality.
The safe choice. Text and vector graphics are untouched and image quality stays close to the original, so savings are modest.
Balanced Compression
Images downsampled to roughly 144 DPI, re-encoded at moderate JPEG quality.
The default. Usually the largest saving you can take without the document looking degraded on screen or in email.
Heavy Compression
Images downsampled to roughly 96 DPI, re-encoded at low JPEG quality.
The smallest practical file, with visible quality loss. Pages that contain no selectable text may be flattened into images, which removes text selection, links and annotations on those pages.
How it works
Choose a PDF
Drag a file onto the box or pick one from your device. It is read locally, not uploaded.
Pick a level
Basic, Balanced or Heavy. Balanced is selected by default and suits most documents.
Download the result
You see the real before and after sizes, then save the compressed file straight to your device.
Frequently asked questions
Are my PDF files uploaded to a server?+
No. Lottinier PDF has no backend for document processing. Your file is read by your browser, compressed by code running on your device, and the result is written straight back to your downloads folder.
Is Lottinier PDF free?+
Yes. There is no account, no subscription and no watermark. The site is funded by advertising.
What is the difference between Basic, Balanced and Heavy Compression?+
They differ in how far images are downsampled and how hard they are re-encoded. Basic targets about 200 DPI at high JPEG quality for barely visible change. Balanced targets about 144 DPI at moderate quality and is the best default. Heavy targets about 96 DPI at low quality, and may flatten pages that contain no selectable text into images.
Why did my PDF not become much smaller?+
Compression works by shrinking embedded images. A PDF that is mostly text and vector graphics, or one that was already optimised, has very little left to remove. In that case Lottinier PDF reports the real result instead of inventing a saving.
Can compression reduce image quality?+
Yes. Images are downsampled and re-encoded as JPEG, which is lossy. Basic keeps quality close to the original, Balanced is a visible compromise only under close inspection, and Heavy is deliberately aggressive.
Can I compress large PDFs?+
There is no hard limit, but everything runs in your browser tab, so very large files are limited by your device memory. Lottinier PDF warns you before starting when a file looks risky and lets you continue anyway.
Does Lottinier PDF work on mobile?+
Yes, on current mobile versions of Chrome, Safari, Edge and Firefox. Phones have less memory than laptops, so warnings appear at a lower file size and very large documents may fail.
Are my files stored anywhere?+
No. Nothing is written to a server, a database or cloud storage. When you close or reload the tab, every trace of the document is gone.
Why can a compressed file sometimes become larger?+
Re-encoding an already efficient image can cost more bytes than it saves. When that happens Lottinier PDF shows the real increase and offers your untouched original for download instead of the larger result.
Does Lottinier PDF support password-protected files?+
No. Encrypted PDFs are detected and reported, and no attempt is made to bypass their protection. Remove the password in your PDF reader first, then compress the file.
More PDF tools are on the way
Merging, splitting, reordering pages and images-to-PDF are in progress, and they will run locally in your browser just like the compressor.