We Compressed 11 Real PDFs in the Browser: Test Results and Which Setting to Use
By PDFtip Team
How much smaller can a PDF actually get when it is compressed entirely inside your browser? Instead of quoting a best-case number, we took 11 real, publicly available PDFs (438 pages, 60.65 MB in total) and ran every one of them through the PDFtip PDF Compressor at two settings. Below are the raw results, what they tell you, and which setting to pick.
How we tested
- Date: October 11, 2026
- Tool: the live PDFtip PDF Compressor at www.pdftip.com, in Chrome on macOS. Compression runs locally with Ghostscript compiled to WebAssembly, so none of the files were uploaded anywhere.
- Settings tested:
- Recommended (Ghostscript
/ebookpreset, images downsampled to 150 dpi) - Maximum Compression (Ghostscript
/screenpreset, images downsampled to 72 dpi)
- Recommended (Ghostscript
- Rule built into the tool: if the compressed file would not be smaller, PDFtip keeps your original file and labels it "Already Optimal" instead of handing you a bigger file.
The test files
| File | Type | Pages | Original size |
|---|---|---|---|
| Attention Is All You Need (arXiv) | Academic paper | 15 | 2.11 MB |
| BERT (arXiv) | Academic paper | 16 | 757 KB |
| Deep Residual Learning (ResNet) (arXiv) | Academic paper | 12 | 800 KB |
| IRS Form 1040 | Fillable form | 2 | 215 KB |
| IRS Form W-9 | Fillable form | 6 | 138 KB |
| IRS Publication 17 | Long text document | 142 | 2.95 MB |
| NASA Artemis Plan | Image-heavy report | 74 | 35.22 MB |
| NIST Cybersecurity Framework 2.0 | Report with graphics | 32 | 1.45 MB |
| USGS Fact Sheet 2023-3005 | Image-heavy fact sheet | 4 | 7.67 MB |
| ERIC ED013371 (Internet Archive) | Scanned document | 130 | 8.92 MB |
| ERIC ED011005 (Internet Archive) | Scanned document | 5 | 485 KB |
Results
| File | Original | Recommended (150 dpi) | Maximum (72 dpi) |
|---|---|---|---|
| Attention Is All You Need | 2.11 MB | 1.26 MB (−40.1%) | 1.23 MB (−42.0%) |
| BERT | 757 KB | 381 KB (−49.6%) | 375 KB (−50.5%) |
| ResNet | 800 KB | 260 KB (−67.5%) | 260 KB (−67.5%) |
| IRS Form 1040 | 215 KB | 129 KB (−39.9%) | 129 KB (−39.9%) |
| IRS Form W-9 | 138 KB | 85 KB (−38.4%) | 85 KB (−38.4%) |
| IRS Publication 17 | 2.95 MB | Already optimal | Already optimal |
| NASA Artemis Plan | 35.22 MB | 7.81 MB (−77.8%) | 2.95 MB (−91.6%) |
| NIST CSF 2.0 | 1.45 MB | 919 KB (−38.0%) | 538 KB (−63.7%) |
| USGS Fact Sheet | 7.67 MB | 3.94 MB (−48.7%) | 3.28 MB (−57.2%) |
| ERIC ED013371 (scan) | 8.92 MB | Already optimal | 3.25 MB (−63.6%) |
| ERIC ED011005 (scan) | 485 KB | Already optimal | 174 KB (−64.0%) |
| Total | 60.65 MB | 27.09 MB (−55.3%) | 15.18 MB (−75.0%) |
Both batches finished in about a minute on our machine, including the 35 MB NASA report. Speed depends on your device, because the work happens on your own computer.
What the numbers tell you
1. Images decide everything. The three image-heavy reports shrank by 71.5% on Recommended and 84.8% on Maximum. The NASA Artemis Plan went from 35.22 MB to 7.81 MB — small enough for most email attachment limits — and down to 2.95 MB on Maximum.
2. Text-only documents barely change between settings. The academic papers and IRS forms gave almost identical results on both settings (about 40–68% smaller). Their savings come from cleaning up fonts and internal structure, not from images, so choosing Maximum gains you nothing and Recommended keeps any figures sharper.
3. Some PDFs are already as small as they can be. IRS Publication 17 is 142 pages of well-optimized text. Neither setting could make it smaller, so the tool kept the original rather than returning a larger file.
4. Scans only shrink on Maximum — check readability first. The two scanned documents did not get smaller at 150 dpi, but dropped by about 64% at 72 dpi. 72 dpi is fine for reading on screen, but small print in a scan can become harder to read, so open the result before you delete the original.
Which setting should you use?
- Recommended for almost everything: documents you will read, print or archive. It gave the full savings on text documents and large savings on image-heavy ones.
- Maximum Compression when you must get under a size limit (email, upload portals) and the file is image-heavy or scanned. Open the result once to make sure it is still readable.
- Already optimal? The file has little left to remove. Splitting it (PDF Split) or deleting unneeded pages (Delete PDF Pages) is the next option.
Limitations of this test
This is a small sample of 11 files, and every PDF compresses differently depending on how it was created. We measured file size only; we did not score image quality numerically. At the time of testing the compressor accepted up to 10 files per batch, so we ran the 11th file separately with the same settings (this limit has since been removed).
Try it with your own files in the PDF Compressor — it runs in your browser and your files are not uploaded.