How to compress a PDF
- Drop a PDF on the box above or click Choose a PDF. The tool shows its page count and size.
- Choose the compression type. Strong makes the file much smaller but turns pages into images. Lossless keeps text and quality exactly but usually saves little.
- For strong compression pick a level: better quality, balanced, smallest, or a size target such as under 1 MB, 500 KB, 200 KB or 100 KB.
- Click Compress PDF. When it finishes you see the size before and after and the percentage saved.
- Click the download button. The file is named after your PDF with
-compressed, for exampleinvoice-compressed.pdf.
Everything runs in your browser. Your PDF is never uploaded, which makes this safe for contracts, ID scans, bank statements and medical documents. There is no sign-up, watermark or daily limit.
The two methods, honestly
A PDF gets big for one main reason: images. A scanned page is a photograph, often 1–3 MB, and a 20-page scan can reach 40 MB. Text and vector graphics are tiny in comparison.
- Lossless rewrites the internal structure with object streams, which packs the document tighter without touching any content. Text stays selectable, links keep working and nothing changes visually. The saving is usually 0–15%, because the big images are left exactly as they are.
- Strong draws each page at up to 150 DPI and stores it as a JPEG, then rebuilds the PDF with the same page sizes. Scans and image-heavy documents typically shrink by 70–95%. The price is that text is no longer text: you cannot select, copy or search it, and tiny print becomes slightly softer.
If you need to keep searchable text in a large scan, run OCR on the original first and compress with a desktop tool that supports image downsampling inside the PDF; a browser tool cannot do that safely.
Size targets and how they work
When you choose a target such as under 200 KB, the tool first draws all pages once. It then tries a ladder of settings from 150 DPI at 80% quality down to 40 DPI at 25% quality. Because file size falls steadily along the ladder, it needs only about five trials to find the best quality that still fits, instead of testing every step. If even the smallest setting is too big, you get that smallest result and a message saying the target could not be reached.
Worked example
A 12-page scanned contract is 18.4 MB and the portal accepts files up to 2 MB. Choose Strong with the target under 1 MB. For a typical scan like this the tool lands on a setting around 100–130 DPI and a file of roughly 1 MB or less, a saving of about 95%, with the same page size as the original; the exact result depends on the scan. At that resolution a contract is still clear on a phone or in print. If the portal needed 100 KB for 12 pages, the smallest result will be quite blurry, so in that case split the document or remove less important pages first.
Tips
- Keep the original. Strong compression cannot be undone. Name and store the compressed copy separately.
- Check readability. Open the result and zoom in on small numbers and signatures before sending it.
- Remove pages you do not need before compressing; fewer pages means a smaller file and a higher quality at the same size.
- Password-protected PDFs must be unlocked first. Open them in a PDF viewer and save an unprotected copy.
- Very long files use a lot of memory in strong mode. On a phone, compress long documents in parts.
Frequently asked questions
Is my PDF uploaded to a server?
No. The file is compressed entirely inside your browser, so contracts, ID scans and statements never leave your device.
What is the difference between strong and lossless compression?
Strong draws every page as an image and rebuilds the PDF from JPEGs: the file can become 5–20 times smaller, but the text can no longer be selected or searched. Lossless only rewrites the file more efficiently and keeps text and quality exactly, so savings are usually small.
Can you guarantee a size such as 100 KB?
It is a best effort. The tool tries progressively lower resolutions and JPEG qualities until the file fits. A long document with many pages may not fit in 100 KB without becoming unreadable, in which case you get the smallest result and a clear message.
Why did my PDF not get smaller?
Files that are already optimised, or that consist of text and vector graphics, have little to save with lossless compression. Try strong compression if you can live without selectable text. If the result is still not smaller, the original is already efficient.
Will the page size or layout change?
No. Every page keeps its original size and layout. Only the internal image quality changes in strong mode.