The short version: you can compress a PDF for free in your browser with Smallpdf, iLovePDF, PDF24, Sejda, PDFgear or PDF Candy, and none of them needs you to install anything. The differences are in the limits and the settings: Sejda caps free use per hour, PDFgear and PDF Candy let you pick how hard to squeeze, and each one says something different about deleting your file.
A PDF that's too big to email is one of those small jobs that eats half an hour if you pick the wrong tool. I've had files bounce back from an inbox limit, and files that came out of a compressor looking like a photocopy of a photocopy. The good news is that there are plenty of free compressors. The trick is knowing which one fits the file you've got, and what each one does with your document once you've uploaded it.
Six free PDF compressors worth knowing
In no particular order:
- Smallpdf: best for a quick browser-based squeeze with nothing to install.
- iLovePDF: best for light use alongside its other core PDF tools.
- PDF24: best for adjusting the compression quality yourself.
- Sejda: best for occasional files with no signup, within its hourly free limits.
- PDFgear: best for choosing between Low, Medium and Strong compression.
- PDF Candy: best for the smallest file size using its Maximum mode.
Compressor limits compared
| Source | Best for | Free plan (as of Nov 2026) |
|---|---|---|
| iLovePDF | Light use with other core tools | Yes |
| PDF Candy | Two compression modes | Yes |
| PDF24 | Adjustable quality | Yes |
| PDFgear | Three compression strengths | Yes |
| Sejda | No signup, hourly limits | Yes |
| Smallpdf | Browser-based, no installation | Yes |
Pages and plans change, so check the vendor's own page before you rely on a limit.
The catch: free means limits, and your file leaves your computer
Every one of these tools is free to start, but free comes with a ceiling. Sejda's page shows a free limit of 30 files per hour and 3 tasks per hour, which is fine for a one-off but not for a batch. Smallpdf's pricing lists limited document downloads on its Free plan, and iLovePDF says its Free Plan is perfect for light use and lets you process a limited number of documents. If you've got a pile of files to shrink, you'll hit a wall quickly on any of them.
The second part of the catch matters more. Every online compressor works by uploading your file to the vendor's servers. So before you upload a contract, a payslip or anything with client details in it, read what the tool says happens next. PDF Candy says all data is automatically erased within two hours, with the option to delete it earlier yourself. PDFgear's download screen says your file will be deleted permanently. Smallpdf describes its compressor as free, secure and browser-based. Those are each vendor's own words, so if the file is sensitive, read their policy in full before you decide.
How to compress a PDF without wrecking it
- Keep a copy of the original file. Compression can't be undone on the smaller copy.
- Check whether the PDF is mostly images or mostly text, because that decides how much it can shrink.
- Pick a tool and start with a medium or default setting, not the strongest one.
- Open the compressed file and zoom in on any photos, charts and small print.
- If it's still too big, run it again on a stronger setting, such as Strong in PDFgear or Maximum in PDF Candy.
- If it still won't shrink, split it into smaller files instead of squeezing it harder.
Why some PDFs barely get smaller
This one confuses people, and PDF24 explains it plainly: PDF files with images can be compressed better than PDF files with text only. A brochure full of photos has plenty of room to shrink. A text-heavy report saved straight from Word often doesn't, because there's little in it to throw away. If a compressor only takes a sliver off your file, that's usually why, and switching tools won't change it much.
For image-heavy files, the setting you choose is a trade-off between size and quality. PDFgear is open about this: its Strong option gives the smallest file size with less quality. PDF Candy's Maximum mode is also aimed at the smallest output. PDF24 lets you adjust the compression quality so you can tune the result. My rule is to go one step stronger at a time and check the file each time, rather than jumping straight to the strongest setting and finding your charts have turned to mush.
When a browser tool isn't the right answer
If you compress PDFs every week, or the files are sensitive, a desktop PDF editor is often a better fit than uploading to a website each time. I've compared the options in my guide to the best PDF editors, and if you're converting between formats as well, my list of the best PDF converters covers the tools that do both. And if you're wondering why so many businesses send everything as a PDF in the first place, here are the benefits of PDFs for business.
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Frequently asked questions
Where can I compress a PDF for free?
Smallpdf, iLovePDF, PDF24, Sejda, PDFgear and PDF Candy all offer free online PDF compression. Each has its own limits, so check the vendor's page before relying on it for a batch of files.
Does compressing a PDF reduce quality?
It can. PDFgear says its Strong compression gives the smallest file size with less quality, and PDF24 lets you adjust the quality to tune the result.
Why won't my PDF get smaller?
PDF24 says PDF files with images can be compressed better than PDF files with text only. A text-heavy PDF may only shrink a little, whichever tool you use.
Is it safe to upload a PDF to an online compressor?
Every online compressor uploads your file to the vendor's servers. PDF Candy says data is erased within two hours and PDFgear says your file will be deleted permanently, so read each vendor's own policy before uploading anything sensitive.
Can I compress a PDF without installing software?
Yes. Smallpdf describes its compressor as browser-based with no installation needed, and the other tools here also run online.
How many PDFs can I compress for free on Sejda?
Sejda's page shows a free limit of 30 files per hour and 3 tasks per hour.
