Compress PDF tools compared: what you choose, and what you get
Every tool here makes a PDF smaller mainly by saving its pictures smaller. They differ in what you choose: a level at iLovePDF, Smallpdf and Adobe, your own settings at PDF24 and Sejda, or, at CECO PDF, one of up to four finished files, each shown with its exact size and a close look at its smallest text.
Which one for which job
- One file, quickly, at no cost: the free use of any of them; PDF24 says it has no limits and needs no registration1.
- Many files at once: iLovePDF compresses up to 10 files at a time on Premium, and Smallpdf Pro includes batch processing2, 3.
- Very large files: Adobe's online tool takes files of up to 2GB, and iLovePDF Premium up to 4 GB a task2, 4.
- Offline: PDF24 Creator, Sejda Desktop or Smallpdf's Windows app5, 6, 7.
- A file that must fit an upload limit and still be read: CECO PDF, which makes the best-looking file under the size you name and never goes below readable to reach it.
The compressors side by side
What each maker's page said on about the choices it gives, its free use, and how long it keeps the files you upload.
Compressing PDFs: what you choose, free use, files kept
| Tool | What you choose | Free use | Your files on its servers |
|---|---|---|---|
| iLovePDF | Extreme, high or regular compression8 | 2 files and 200 MB a task2 | Deleted within two hours9 |
| Smallpdf | Basic; Moderate and Strong on Pro10 | A limited number of downloads11 | Deleted after one hour10 |
| Adobe Acrobat online | High, Medium or Low4 | Free with limited use; files up to 2GB4 | Deleted unless you sign in and save it4 |
| PDF24 | Resolution, image quality and a list of options12 | No limits, no registration1 | Deleted after one hour12 |
| Sejda | Image quality: pictures saved at JPEG quality 65%, or “Good” or “Best”13 | Up to 200 pages or 100 MB, and 3 tasks an hour13 | Deleted after 2 hours13 |
| CECO PDF | Up to four finished files, each with its exact size, or the best one under a size | Files of up to 100 MB and 50 pages without a plan; its download rule is below | The sizes it makes are kept for an hour; the one you choose until you erase it, for 90 days at most |
iLovePDF
iLovePDF's guide offers three levels, extreme, high or regular, and says plainly that the higher the compression, the lower the file size and the quality8. Its free use compresses 2 files at a time, with up to 200 MB a task; Premium takes 10 files and up to 4 GB2. Files are deleted within two hours of processing9. The pages we read do not mention a preview of the result before you download it.
Smallpdf
Smallpdf offers Basic compression on the free plan, and Moderate and Strong on Pro, and compresses Word, PowerPoint and Excel files and images as well as PDFs10. It says usage limits may apply, and that files are deleted after one hour10. Pro includes batch processing3, and the Windows app compresses offline, with basic and strong compression7.
Adobe Acrobat online
Adobe's online compressor offers High, Medium and Low levels, takes files of up to 2GB, and is free with limited use4. Adobe says no sign-up is needed for basic compression unless you want to save the document, and that files are deleted from its servers unless you sign in to save them4. The page we read does not mention a preview of the result before you download it.
PDF24
PDF24 lets you set the resolution and the image quality yourself, with a list of further options, such as turning pictures to greyscale or taking out bookmarks, annotations or metadata12. Its online tools say they are free, with no limits and no registration1, and that files are deleted after one hour12. PDF24 Creator compresses offline on Windows5.
Sejda
Sejda saves the pictures in a PDF at a JPEG quality of 65%, and you can choose “Good” or “Best” for better pictures and a larger file13. Its free use takes documents of up to 200 pages or 100 MB, 3 times an hour, and files are deleted after 2 hours13. Sejda Desktop compresses files of up to 100MB on your own computer, free with daily limits6.
CECO PDF
CECO PDF makes the smaller files before it shows you anything, then offers up to four, largest first. Each one is a real file rather than a guess, shown with its exact size, the share it saves and what it gives up, beside a close-up at actual size of the smallest, densest text in your file and the same spot in the original. The first looks like your file; the last is as small as it can be with every word still readable. Compressing, in detail.
If a form has an upload limit, pick a size between 100 KB and 10 MB, or type one in, and it makes the best-looking file below that size. Readability wins over the number: when a size cannot be met with every word still readable, it tells you how close it can get, and offers to split the file into parts under that size. Text stays text, and no picture is made larger or saved at a higher quality than it had. There are pages for limits of 100 KB, 200 KB and 1 MB.
It takes files of up to 100 MB, with as many pages as your plan allows in one document: 50 without a plan. Downloading costs nothing when the files you started from have no corrections made here. A file made from a corrected document is priced as one. What a credit and each plan cost is on the pricing page. The sizes it makes are kept for an hour, or until you pick one, and the file you pick stays with your documents for 90 days at most, or until you erase it.
Compress a PDF now — it opens the tool, with nothing to install.
When another tool is the better choice
- Many files at once. iLovePDF and Smallpdf process files in batches on their paid plans2, 3; CECO PDF compresses one file at a time.
- Office files and images. Smallpdf compresses Word, PowerPoint and Excel files and images directly10; CECO PDF compresses PDFs.
- Very large files. Adobe's online tool takes up to 2GB, and iLovePDF Premium up to 4 GB a task2, 4.
- Offline. PDF24 Creator, Sejda Desktop and Smallpdf's Windows app work without an internet connection5, 6, 7; CECO PDF runs only in the browser.
- Full control of the settings. PDF24 lets you set the resolution, the picture quality and a list of options yourself12; CECO PDF chooses the settings and shows you the results to choose from.
How we checked
On we read each maker's own pages, listed under Sources: prices, product pages, help pages and their questions and answers. Every statement about another tool comes from those pages, quoted where the exact words matter, and where they do not say something, neither do we. We did not upload files to any of these tools: this compares what each maker says its tool does, not our own tests of it. We chose the online compressors people most often weigh against each other when they search for a way to compress a PDF.
Prices are the ones each page showed us, in the currency it showed. They can differ by country, tax and offer, so check the maker's page before you buy. Facts about CECO PDF come from the service itself: its prices, limits and how long it keeps files are read from its own settings each time this page is served. If something here is out of date, the page is corrected and dated again.
Sources
Each page below was read on , on its maker's own website. A number in the text leads to the page the fact came from.
- PDF24: Merge PDF. tools.pdf24.org/en/merge-pdf
- iLovePDF: Pricing, with the plans compared. www.ilovepdf.com/pricing
- Smallpdf: Smallpdf Free and Pro compared. smallpdf.com/blog/smallpdf-free-vs-pro-plan-comparison
- Adobe: Acrobat online: compress a PDF. www.adobe.com/acrobat/online/compress-pdf.html
- PDF24: PDF24 Creator. tools.pdf24.org/en/creator
- Sejda: Sejda PDF Desktop. www.sejda.com/desktop
- Smallpdf: Desktop app for Windows. smallpdf.com/download/windows
- iLovePDF: User's guide to the tools. www.ilovepdf.com/help/documentation
- iLovePDF: Security and data protection. www.ilovepdf.com/help/security
- Smallpdf: Compress PDF, and its questions and answers. smallpdf.com/compress-pdf
- Smallpdf: Pricing and plans. smallpdf.com/pricing
- PDF24: Compress PDF. tools.pdf24.org/en/compress-pdf
- Sejda: Compress PDF. www.sejda.com/compress-pdf
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