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Reduce PDF Size Without Losing Quality
A smaller PDF is easier to email, upload, and share. But compression should not make important text, images, stamps, or signatures unreadable.
By GaryLast updated 5 min read
Compress a PDFHow to compress a PDF and keep it readable
- Open Compress PDF and select Select PDF File, or drop the PDF onto the box.
- Under “How small should it be?”, leave Balanced selected for the first try. If you were given a maximum size, choose Fit a size limit and pick the limit instead.
- Select Compress PDF. When it finishes, the result reads “Your PDF is ready” and shows the new size, the original size and the percentage saved.
- Look at the Before and after panel underneath, which puts each page next to its original, then select Download PDF. The copy is saved with -compressed at the end of its name.
- Open the copy and zoom in on the smallest text, any signature and any stamp before you send it.
What compression does to your pages
It helps to know how the PDFAreUs compressor works before you rely on it. Nearly all the weight of a large PDF is in its pictures: scanned pages, photos, logos. The compressor stores those pictures at a lower resolution and a lower JPEG quality, and leaves everything else as it was. Balanced keeps pictures at about 150 dpi and Strong at about 110 dpi, which is why Balanced looks sharper and produces a bigger file.
That has three consequences worth knowing. Text stays real text, so it can still be selected, copied and searched, and it stays as sharp as it was. Links, fillable form fields and bookmarks keep working. And the pictures lose some fine detail, especially with Strong; on a scanned page the words are part of the picture, so very small print is the first thing to soften.
There is one exception. If you set a size limit and the file cannot reach it any other way, the tool offers to turn every page into a picture. That can go much smaller, but text in that copy can no longer be selected or searched, and links and form fields are gone. It only happens if you choose it, after a warning.
Tips to keep quality high
- Start with a clear original file.
- Avoid compressing the same PDF many times.
- Remove unnecessary pages before compressing.
- Use JPG to PDF only when images are needed.
- Check the final PDF before submitting it.
When quality matters most
Quality is especially important for resumes, certificates, passports, IDs, immigration files, invoices, signed forms, school assignments, and legal documents.
Why some PDFs shrink a lot and others barely change
Most of a large PDF’s size is usually images: scanned pages, photos, logos exported at print resolution. Compression works mainly by storing those images more efficiently, so image-heavy files shrink the most.
A PDF that is mostly real text, such as a report exported from Word, is often small already. If the compressor says “This PDF is already as small as it gets”, that is normal for this kind of document: the original is fine to send. The tool never hands you a file that is bigger than the one you started with.
Balanced, Strong or a size limit?
Start with Balanced, which keeps better quality. Check the result: zoom into small print, signatures and stamps. Only switch to Strong if the file is still too large for where it is going. If you know the exact maximum, Fit a size limit saves the guesswork: it uses the gentlest compression that gets the file under that number.
- Balanced: contracts, certificates, anything with fine print or signatures.
- Strong: long scans and photo-heavy handouts.
- Fit a size limit: an upload form or mailbox that states a maximum, such as 1 MB or 5 MB.
Why scanned PDFs become large
When you scan documents, each page may be saved as a high-resolution image. This can make even a short document very large, especially if it includes colour pages, photos, signatures, stamps, or multiple scans.
How the compressor treats a scan
A scanned page is one large picture. The compressor stores that picture at a lower resolution than most scanners use, and at a lower JPEG quality, which is where the saving comes from. Nothing changes about how you use the file: it looks the same, just lighter. Strong uses a lower resolution and a lower JPEG quality than Balanced, so very small print is the first thing to soften.
Some scans barely change. Pure black-and-white scans, the kind a fax or an office copier often makes, are already stored very compactly, and the compressor leaves them as they are rather than risk making them worse.
Scan smaller in the first place
Scanner and phone settings decide most of a scan’s size. If you are about to rescan, a few choices make the file much lighter before compression even starts.
- Use greyscale or black and white for text documents; colour multiplies the size.
- Use a normal document resolution rather than the scanner’s maximum photo setting.
- Scan only the pages you need, and skip blank backs of single-sided pages.
Phone scans
A phone photo of a page is usually far larger than the page needs to be. Photograph on a flat surface in even light so the page fills the frame, then turn the photos into one PDF with Scan to PDF or JPG to PDF and compress the result.
Documents to review carefully
Review passports, IDs, certificates, immigration forms, legal papers, receipts, invoices, and signed documents after compression. If any important detail looks blurry, use a clearer scan or split the document into smaller files.
Do not over-compress scanned documents if signatures, stamps, names, or dates become hard to read.
Getting the text out of a scan
Compression does not make text in a scan selectable, and the result screen says so: for a scan it notes that the PDF has no selectable text. If you need the words themselves, for example to paste them into a form, use OCR PDF: it recognises English text in the scan and gives it to you as text you can copy or download as a .txt file. OCR runs in your browser, so it is slower than compression, but the document never leaves your device.
Reduce the content before compressing it
The cleanest way to keep quality is to send less. Remove pages the recipient does not need, extract only the relevant section, and delete blank scanned pages. A shorter file can then use the lighter compression level and still fit.
Keep the original
Save the compressed copy under a new name and keep the original. If someone later asks for a clearer copy, or you need to print it, you still have the full-quality version.
If it still doesn't work
- “This PDF is already as small as it gets”: the file is mostly text and already compact. Send the original.
- Small print or a signature is blurred: go back to the original and use Balanced, or remove pages first so the lighter setting is enough.
- Still too large on Strong: choose Fit a size limit and enter the maximum. If the tool says the file is still over your limit, split it with Split PDF and send it in parts, or remove pages you do not need with Remove Pages.
- The recipient needs to search or copy the text: the compressed copy keeps its text, so you can send it. Only a copy made with Turn pages into pictures loses it.
- The browser runs out of memory on a very long file: compression happens on your device. Close other tabs, or split a long file into parts and compress each one.
Frequently asked questions
Can a PDF be compressed with no quality loss at all?
The text, links and form fields are not changed at all. Photos and scans inside the PDF are stored at a lower resolution, so they lose a little detail. The loss on Balanced is small for most documents; check the result at full zoom before you send it.
Will my text still be selectable?
Yes. Text you could select before can still be selected, copied and searched, because only the photos and scans inside the PDF are stored smaller. The one exception is the Turn pages into pictures option, which the tool offers only when a size limit cannot be met any other way and which warns you first.
Is my file uploaded?
No. Compression runs in your browser and the file stays on your device.
Which level should I use for a scan?
Try Strong for typed or printed pages and check the result. Use Balanced for scans with small print, handwriting, photos or official stamps.
Can I compress the same scan twice?
You can, but each pass loses a little more detail. Compress the original again with a different level instead.