Compress PDF
Free Private Works Offline
100% client-side processing, so zero server uploads ever. Drop in one or more PDFs and download smaller versions in seconds, with text that stays selectable and searchable.
Choose PDFs or drag them in
PDF only · nothing is uploaded
Compression Level
Largest Image Side
px
Image Quality
%
Total for all files
Original Size:
—
After Compression:
—
Size Savings:
—
Pages:
—
Text Preserved:
—
Scanned Pages:
—
How it works
- Choose one or more PDFs and they are compressed right away in your browser. Change the level any time to compress them again.
- Photos inside the PDF are resized and recompressed. Text and vector graphics are never turned into images, so text stays selectable and searchable.
- Each result is checked against its original before you can download it. If anything differs, or the file can't get smaller, your original is kept.
- Use the Difference Slider to compare a page of the original and the compressed PDF. Drag the slider, or focus it and press + or − to zoom. With several PDFs, tick "Use Difference Slider" above the files.
- Download one PDF on its own, or all of them together as a ZIP.
- Nothing is uploaded. Once the page has loaded, it keeps working offline.
Frequently asked questions
- Is my PDF uploaded anywhere? No. Compression runs entirely in your browser. Your file is never sent to a server, so it stays private.
- Will the text stay selectable and searchable? Yes. Pages are never converted to images. Only the photos embedded inside the PDF are recompressed, while text and vector graphics are left untouched.
- Why did my file shrink only a little, or not at all? Text-only PDFs are already small, and most of the weight in other PDFs is in images. If a file is already well optimized, the original is kept so it never gets bigger.
- Can I compress several PDFs at once? Yes. Add as many PDFs as you like, and download them together as a ZIP or one at a time.
- What is Target Size? Set a file size you want, such as 500 KB, and the tool tries several settings until it gets under that size, then shows you the closest result it could reach.
- Do you optimize fonts and scanned pages? Yes. Unused characters are trimmed from embedded fonts where it is safe to do so, and scanned or photographed pages are recognized and compressed more effectively.
- Which PDFs are not supported? Password-protected PDFs cannot be processed. Digitally signed PDFs can be compressed, but rewriting the file invalidates the signature.
What happens to your PDF
- Photos: each photo is shrunk to the size it is actually shown at on the page (72, 150 or 300 DPI, depending on the level), then saved again as a lighter JPEG. Photos are never enlarged.
- Internal data: the PDF's hidden data blocks, such as fonts and page instructions, are packed again with a stronger compressor, so even a PDF without photos can get a little smaller.
- Fonts: with Optimize Fonts on, unused characters are removed from fonts embedded in your PDF, where it is safe to determine which characters are used. Every font change is checked against how your PDF looks, and undone if anything looks different.
- Scanned and photographed pages: a page that is really one big image with little or no real text is recognized as scanned, and its image is compressed as a photo would be, including converting it to grayscale first when it has no real colour to keep.
- Faxed or scanned black-and-white images: images stored in the scanner formats CCITT and JBIG2 are decoded and, when doing so makes them smaller, recompressed. When the original is already smaller, it is kept as is.
- Clean-up: identical copies of the same photo or font are merged into one, and leftover data from old edits is removed. If you keep the tick box on, author details and page thumbnails go too.
- Left alone: text and vector graphics are never touched or turned into images. Links, bookmarks, forms and page sizes stay as they were.
- Safety check: the result is opened again and compared with your original, covering text, page count, page size, rotation and links. If anything differs, or it can't get smaller, you get your original back.
How to get the most out of it
- Start with Middle. Move to Extreme only if the file is still too big, and to Light if it will be printed.
- Check the result. Use the Difference Slider to zoom into a page with photos before you download. Use the page arrows to reach later pages.
- Expect the biggest savings on PDFs with photos or scans. Text-only PDFs are already small, so they usually shrink by a few KB to a quarter of their size.
- Compress your original. Compressing a file that was already compressed rarely saves much and can only lower photo quality further.
- Use Custom for exact control. Lower "Largest Image Side" for scans, or raise "Image Quality" if photos look blocky.
- Do many at once. Add all your PDFs together and download them as one ZIP.
- Try Target Size for a size limit. Enter the size you need, such as for an email attachment or an online form, and the tool searches for a setting that fits.
- Know the limits. Password-protected PDFs can't be compressed, and digitally signed PDFs lose their signature when rewritten.
How it compares with iLovePDF
- Privacy: iLovePDF uploads your PDF to its servers and deletes it automatically after 2 hours. Here nothing is ever uploaded. Your PDF stays on your device.
- Levels: both offer Extreme, Middle and Light compression. This tool adds a Custom option for your own image size and quality.
- Limits: iLovePDF says unlimited batch processing needs Premium or its desktop app. This tool needs no account, has no daily limit and adds no watermark. Your device's memory is the only limit.
- Offline: iLovePDF offers a separate desktop app for offline use. This page keeps working offline once it has loaded, and can be installed as an app from your browser.
- Checking quality: this tool shows a before and after Difference Slider and checks every result against your original before you download.
- What iLovePDF has that this doesn't: a large set of other PDF tools, such as merge, split and convert, plus desktop and mobile apps. This page does one job only.
- Results: both shrink photos and tidy internal data, so how much you save depends on your file. Try your own PDF to see.
How it compares with other popular PDF compressors
- Smallpdf: works in the cloud and deletes files after one hour. Its Basic level is free, while Moderate and Strong compression need a Pro plan. Here every level is free.
- Adobe Acrobat online: handles your file on Adobe's servers and deletes it unless you sign in to save it. It offers High, Medium and Low levels and files up to 2 GB.
- PDF24: its online tools upload your file and delete it after one hour, and it advertises no usage limits. Its free PDF24 Creator app works offline on Windows.
- The main difference: these sites process your PDF on their servers, so it has to be uploaded first. Here it is processed inside your browser, which matters most for contracts, ID documents and other private files.
- Trade-off: a cloud service does the work on its own servers, so it can handle extremely large PDFs more easily. Here, very large files depend on your device's memory and may be slow on a phone.
- Note: these details come from each service's own website as of September 2026 and can change.