How to compress PDF online
To compress a PDF, open it in the tool and pick a level. Basic keeps images at full resolution and high quality while cleaning up the file. Balanced re-encodes embedded photos at a lower resolution, which is where most of the size usually hides. Strong rasterises each page for the smallest result. The estimated new size appears as soon as you pick a level, worked out on your own device, and you can add several files and compress them together.
Step by step
Three steps. Most files take a few seconds.
Step 1: Open your PDF
Drop the file onto the page. The current size is shown immediately.
Step 2: Pick a compression level
Basic keeps images sharp and only trims the fat. Balanced is the default and works for most scans and reports. Strong gives the smallest file. The estimated new size updates as you switch.
Step 3: Compress and download
Click Compress PDF and download. Several files come back together as a zip.
Why use this tool
Choose the trade-off
Three clear levels instead of a mystery slider, with the real result size shown before you commit.
Images are the target
Balanced mode downsamples photos and scans, which is usually 90 percent of a large PDF, while leaving text crisp.
Nothing is stored
Bank statements and contracts stay private. The file is gone once you download the result.
Your file is never stored
Your document is used only to produce the result you asked for. Once the download is ready and you leave the page, the file is gone. There is no copy to keep, no account that holds it, and nothing to delete later.
That makes it safe for invoices, contracts, bank statements, ID scans, medical records, and anything else you would rather keep to yourself.
Read how it worksFrequently asked questions
How do I reduce a PDF file size without losing quality?
Use the Basic level. It rebuilds the file, removes unused data, subsets fonts, and re-encodes images at high quality without lowering their resolution, so pages look the same at any zoom. For scans, Balanced usually looks the same on screen while cutting the size by half or more.
How small can the PDF get?
It depends on what is inside. A PDF full of photos can shrink by 60 to 90 percent in Balanced mode. A text-only PDF that is already optimised may only shrink a little.
Can I compress a PDF to under 100 KB or 1 MB?
Start with Balanced and check the result. If it is still too large, use Strong, which rasterises pages at screen resolution. For a specific target size, run the tool again on the output.
Does Strong mode keep selectable text?
No. Strong mode converts each page into an image, so text can no longer be selected or searched. Use Basic or Balanced if you need to keep text.
Is it safe to use this with confidential documents?
Yes. Your file is used only to produce the result you asked for and is never stored. We do not keep copies, read the contents, or share them with anyone. Once you download the result and close the page, the file is gone.
Is this really free?
Yes. Every tool on PDF Editor Box is free to use without signing up. We may show an ad outside the work area, but we never gate features, add watermarks to your output, or limit how many files you process.