Honest compression
PDF size is mostly images: photos, scans and logos. Text takes very little space. So the amount you can save depends on the file. A scanned contract or a brochure full of photos can often shrink by 70–90%. A text-only report may barely change, because there is little to remove. SmallKits shows the size before and after, and if the result would not be meaningfully smaller, it tells you instead of giving you a file that is the same size or bigger.
Three levels
- Light keeps text and quality, gently recompressing large photos. Good for documents you will print.
- Recommended keeps text and reduces photos to a sensible size for screens and email. The best balance for most files.
- Strongest turns every page into a compressed image. It gives the smallest files, especially for scans, but text can no longer be selected, searched or copied. Use it for scans and when size matters most.
Need it under a size?
Upload forms often say “maximum 2 MB”. Type the target size and SmallKits tries stronger levels until the file fits, asking before it turns pages into images.
Private, unlimited, no size cap
Compression happens in your browser, so the PDF is never uploaded and there is no daily limit. Very large files (hundreds of megabytes) work best on a computer; phones may be slow.
Tips for smaller PDFs
- When scanning, choose 150–200 dpi and black and white for text documents.
- Making a PDF from photos? Use Images to PDF with “Smaller file” and the scan clean-up; it is smaller from the start.
- Remove pages you do not need with Split PDF.
A worked example
A visa portal accepts PDFs up to 2 MB, and your scanned bank statement is 9.4 MB. You drop it on the page, leave “Recommended” selected and type 2 in the target size. SmallKits recompresses the scanned images and saves a 1.6 MB file, showing “9.4 MB → 1.6 MB (83% smaller)”. Your text-only company report, on the other hand, is already 300 KB; the tool tells you it is already well compressed rather than giving you a file that is no smaller.
How compression works here
PDFs store photos and scans as images inside the file. In Light and Recommended mode, SmallKits finds the large JPEG images, resizes those that are much larger than needed for reading on screen, and saves them at a sensible quality. Text, vector drawings and fonts are left untouched, so text stays sharp, searchable and selectable. The PDF’s internal structure is also packed more efficiently.
In Strongest mode, each page is drawn as an image at screen resolution and saved as a compressed JPEG. This gives the biggest savings for scans and complex pages, but the result is effectively a picture of each page.
Which level should I choose?
| Your file | Choose |
|---|---|
| Brochure, catalogue or report with photos | Recommended |
| Document you will print | Light |
| Scanned pages, photos of documents | Recommended, then Strongest if still too big |
| Must be under a size limit | Type the target size |
Why on-device matters
The files people compress are often the ones they need to upload somewhere official: IDs, statements, payslips and certificates. Compressing them on a free website first means uploading them twice. With SmallKits, they never leave your device until you choose where to send them.
Limits
Some PDFs store images in formats that this tool leaves as they are, so savings vary. Password-protected PDFs need to be unlocked first. Very large files are best compressed on a computer.
Terms explained
- DPI
- Dots per inch: how much detail an image has when printed. 150 dpi is plenty for reading on screen.
- Rasterise
- Turn a page into an image, as Strongest mode does.
Before you compress
Check whether you need every page; removing pages with Split PDF is often the biggest saving of all. If the PDF came from photos, rebuilding it with Images to PDF on “Smaller file” usually beats compressing afterwards. And keep your original: compression is one-way, so if you later need a sharper print, you will want the full-quality file.
Related free tools
- Free merge PDF tool: combine several files into one, then compress the result once.
- Free split PDF tool: remove pages you do not need before compressing.
Updated 2026-10-29