What is the Compress PDF?
A PDF compressor shrinks the size of a PDF file so it is easier to email, upload and store. Large PDFs are a daily headache: email providers reject attachments over 20–25 MB, job and university portals cap uploads at 5–10 MB, and scanned documents with high-resolution images can balloon to hundreds of megabytes. Compression solves this by re-rendering pages at a lower resolution and JPEG quality, trading a controlled amount of sharpness for a dramatically smaller file.
On BConvert, compression happens entirely in your browser. Nothing is uploaded to any server, so confidential contracts, medical records and financial statements never leave your device. You pick a quality level between 10 and 90 percent and a render scale, and the tool rebuilds your PDF page by page from optimized images. The result screen shows the exact before and after sizes plus the percentage saved, so you always know what the trade-off bought you.
The quality slider is the heart of the tool. A setting of 60–70% is the sweet spot for most documents: text stays perfectly readable while file size typically drops by 50–80%. Push it down to 20–30% for a draft you only need on screen, or keep it at 80–90% when the PDF will be printed. The render scale matters too — small is fastest and produces the tiniest files, while high preserves fine detail in diagrams and photos at the cost of less savings.
One honest limitation you should know: because pages are re-rendered as images, text in the compressed PDF is no longer selectable or searchable. If you need to keep the text layer, use the high quality setting and accept a smaller saving, or compress only when the PDF is destined for reading and printing rather than editing. For scanned PDFs — which are already images — there is no downside at all, and size reductions of 70% or more are common.
Compression is not always the right move, and knowing when to skip it saves frustration. If the PDF is already small, or if it is mostly vector text with few images, the savings may be negligible — check the before-and-after numbers and keep the original if the difference is small. And if the document must remain searchable or you need to copy text from it, compression is the wrong tool entirely, since the text layer is removed. In those cases, splitting the PDF or removing unneeded pages with a PDF splitter achieves smaller files without touching text quality. For everything else — scanned paperwork, image-heavy reports, photo portfolios — compression is the fastest path from an unshareable file to one that sails through email and upload forms.
How to use it
- Drop your PDF onto the tool — Drag and drop the file or click the drop zone to choose it. It never leaves your browser — processing is 100% local.
- Set the JPEG quality — Use the slider (10–90%). 60–70% is the recommended balance of size and readability for everyday documents.
- Choose a render scale — Small is fastest with the biggest savings; Medium is the all-rounder; High keeps fine detail sharp for printing.
- Wait for the compression — Pages are processed one by one. Larger documents take longer — keep the tab open until it finishes.
- Check the savings and download — The tool shows before/after sizes and the percentage saved. If the file grew instead of shrinking, lower the quality and run it again.
Common use cases
- Shrinking a scanned contract so it fits under a 10 MB upload limit
- Compressing a photo-heavy brochure before emailing it to a client
- Reducing a thesis or portfolio PDF for a job application portal
- Making large ebooks and manuals take less phone storage
- Preparing print-ready files that are still easy to share online
Tips
- Start at 60% quality — it is the sweet spot for readable text and big savings
- Scanned PDFs compress best; digitally-created PDFs with lots of vector graphics save less
- If quality looks poor, raise the render scale before raising the JPEG quality
- Compress a copy of your file and keep the original for printing
- Text becomes unselectable after compression — keep the original if you need to copy text later
- For multi-hundred-page PDFs, process in smaller batches if your browser feels slow
Frequently asked questions
How do I compress a PDF to under 10 MB?
Upload your PDF, set quality to around 50–60% with Medium scale, and check the before/after sizes. If it is still over 10 MB, drop the quality to 30–40% or use the Small scale and compress again.
Does compressing a PDF reduce its quality?
Yes, slightly — pages are re-rendered as JPEG images, so very fine detail softens at low quality settings. At 60–70% quality, text remains crisp for on-screen reading and the size typically drops by 50–80%.
Is it safe to compress confidential PDFs online?
With this tool, yes — everything runs in your browser and your file is never uploaded to any server. Close the tab and nothing of your document remains anywhere.
Why is my compressed PDF not selectable as text?
Compression rebuilds pages as images, which removes the text layer. This is expected behavior. Keep your original file whenever you need selectable or searchable text.
How do I reduce PDF file size for email attachments?
Upload your PDF, pick a quality level, and download the smaller file — ideal for email limits like 10 or 25 MB.
Can I compress a PDF without uploading it to a server?
Yes. Compression runs 100% in your browser, so your PDF is never uploaded anywhere.
How do I reduce PDF file size for email attachments?
Upload your PDF, pick a quality level, and download the smaller file — ideal for email limits like 10 or 25 MB.
Can I compress a PDF without uploading it to a server?
Yes. Compression runs 100% in your browser, so your PDF is never uploaded anywhere.
📖 Step-by-step tutorial: read our guide How to Compress a PDF Online for Free.