How to use the Compress PDF tool
- 1
Add your PDF
Drop a PDF into the box or choose it from your phone or computer.
- 2
Choose a level or a target size
Pick Light, Recommended, Strong or Maximum – or switch to Target size and enter the limit in KB that your form allows.
- 3
Compare the sizes
See the original and the new file size side by side. If the PDF can't be made any smaller, the tool tells you.
- 4
Download
Save the compressed PDF, ready to attach or upload.
Why use KBSnap’s Compress PDF?
Four compression levels
From a gentle Light setting to Maximum for scans, so you choose how much quality to trade for size.
Target size in KB
Enter the limit your portal sets – 100 KB, 200 KB, 1 MB – and compress towards that number.
Text stays selectable
Light, Recommended and Strong only recompress the images, so the text remains searchable and sharp.
Maximum mode for scans
Turns each page into a compressed image – the most effective option for scanned documents.
Clear before-and-after
Original and new size are shown together, and you're told honestly when a file can't shrink further.
No upload
Compression happens on your own device. Your PDF is never sent to a server or stored online.
Why are some PDFs so large?
Text takes up almost no space in a PDF. What makes files heavy is almost always the images embedded inside them. A long report exported from a word processor can be smaller than a three-page scan, because the scan is really three large photographs wrapped in a PDF.
- Scanned documents: every page is stored as a full-page image, often scanned at a high resolution and in colour, even when the page is black text on white paper.
- PDFs made from phone photos: each page carries the full resolution of the camera, which is far more than you need to read a document.
- Photos and graphics: brochures, portfolios and presentations often contain print-quality images that are much larger than a screen needs.
- Embedded fonts: fonts are included so the document looks the same everywhere. They add some weight, but much less than images.
That's why compressing a PDF mostly means compressing its images. It also explains why some files barely shrink: a PDF that's nearly all text and simple vector graphics is already compact, and there's little left to remove. When that happens, the tool tells you instead of handing back a file that's no smaller.
Compression levels explained
Each level balances file size against quality differently. If you're unsure, start with Recommended and only go further if you need to.
| Level | What it does | Text selectable? | Best for |
|---|---|---|---|
| Light | Gently recompresses the images inside the PDF | Yes | Documents with photos where quality matters, or files you'll print |
| Recommended | A balanced recompression of the images | Yes | Email attachments and everyday sharing |
| Strong | Compresses the images harder for a smaller file | Yes | Image-heavy files and upload limits, when some softness is acceptable |
| Maximum | Converts every page into a compressed image | No | Scanned documents and the strictest size limits |
The trade-off with Maximum mode
Maximum works differently from the other levels. Instead of recompressing the pictures inside the PDF, it turns each whole page into a compressed image. That gives the biggest savings, especially for scans, but the text in the result is no longer selectable: you can't search it, copy it or highlight it, and any clickable links or fillable fields in the original won't work in the compressed copy.
For a scanned document this usually costs nothing, because the text in a scan was a picture to begin with. The exception is a scan that was made searchable with OCR software – Maximum removes that searchable layer. For documents created digitally, such as a contract exported from Word, try Recommended or Strong first and keep the original in case you need the text later.
Which setting for which job?
- Emailing a report or presentation: Recommended. Email services usually cap attachments at around 20–25 MB, and a smaller file is easier to open on a phone.
- Sending a scanned contract or form on WhatsApp: Strong, or Maximum if the scan is still heavy.
- Uploading to a portal with a KB limit: Target size, with the portal's exact limit.
- Keeping a copy you might print: Light, so photos and fine print keep their detail.
- Archiving digital documents you may need to search later: Light or Recommended – avoid Maximum so the text stays selectable.
Compress a PDF to a specific size in KB
Upload forms rarely care about quality levels – they care about a number. Job applications, exam registrations, university admissions and government portals often cap each document at a limit such as 100 KB, 200 KB, 500 KB or 1 MB. Switch to Target size, enter that limit in KB and the compressor works towards it, then shows you the size it reached.
How small a PDF can go depends on how many pages it has and what's on them. A few scanned pages can usually be brought down a long way; a 30-page scanned document may not fit under a tiny limit while staying readable. For the most common upload limits there are ready-made pages: compress PDF to 100 KB and compress PDF to 200 KB.
What to do if your PDF is still too big
- Move up a level. Try Strong, then Maximum if the file is a scan and you don't need selectable text.
- Send fewer pages. If the portal only needs certain pages, extract them with Split PDF and compress the shorter file.
- Rebuild PDFs made from photos. Recreate the PDF with JPG to PDF using the Small file image quality, or shrink the photos first with Compress Image.
- Scan smarter. For text documents, scanning in greyscale at 150 DPI produces a far smaller file than colour at 300 or 600 DPI, and it's still clearly readable.
- Start from the original. Compressing an already-compressed PDF again and again gives diminishing savings and lowers quality each time.
Is it safe to compress PDFs online?
The PDFs people need to shrink are often the private ones: bank statements for a visa application, signed contracts, payslips, scans of passports and national ID cards. Most online compressors upload those files to their servers to process them.
KBSnap compresses your PDF inside your browser. The file is processed on your own phone or computer and is never uploaded, so no copy is left on anyone else's server. That doesn't replace looking after the file on your own device and in your email, but it does remove one place where your documents could otherwise end up. There's no sign-up, no watermark and no daily limit.