PDF tool checks, sample files and limitations
Try the tools with the non-personal sample files below before using your own documents. Follow the settings and compare your result with the downloadable outputs. PDF168 maintains these checks of the processing functions used by the site and its compression service. They are not independent certification or a guarantee for every document.
Choose the right processing mode
- Do not want to upload documents? Choose a tool labelled Local processing, such as Merge, Split, Rotate or Images to PDF. Documents stay on your device, although code or fonts may need to download first.
- Need compression or Office conversion? These tools send files to the processing server over HTTPS and require an internet connection.
- Using AI? Document text or page images are sent to an AI service. Translation to Word also uploads the PDF. AI can make mistakes; check its answers against the original.
Reproducible checks
Local processing functions ran in Node 22.23.0; the compression check called the site's live service. Checks cover page counts, dimensions, ordering and rotation. This is not a browser speed benchmark and does not cover every PDF feature.
Sample A: 2 pages, different sizes · Sample B: 1 page · Synthetic sample image
| Tool | Input and settings | Result |
|---|---|---|
| Merge PDF | Add A, then B | 3 pages: A1 → A2 → B1; page sizes preserved |
| Split PDF | Use merged.pdf; enter 3,1 | 2 pages: B1 → A1 |
| Rotate PDF | Use merged.pdf; rotate only page 2 by 90° clockwise | 3 pages; only page 2 rotated |
| Images to PDF | sample-image.jpg | 1 page, 1200 × 1600 pt |
| Compress PDF | image.pdf, compression level 5 | 965.3 KB → 85.9 KB |
View the raw check record (JSON)
The compression sizes apply only to this synthetic image example. Text PDFs, already-compressed files and signed documents can behave differently or become larger. Compare quality, size and content before keeping the output.
Which tool fits your task?
- Combining a document and its attachments?
- Use Merge PDF and the ▲/▼ buttons to order files. It appends whole documents. Use Split PDF first if you only need selected pages.
- Need a smaller file for an upload limit?
- Try Compress PDF at a moderate level and compare the output. Compression cannot guarantee a target KB/MB size; image quality, resolution and existing compression affect the result.
- Cannot select text in a scanned PDF?
- Scans often contain images without a text layer. OCR is needed to recognise text. Images to PDF and Merge PDF do not automatically perform OCR.
What these checks do not establish
- Preservation of encryption, digital-signature validity, PDF/A compliance, interactive forms, bookmarks and accessibility tags. Keep your originals and separately validate important documents.
- Performance with very large files or every phone and browser. Reduce batch size if device memory is insufficient.
- Complete accuracy of AI answers or automatic redaction. Detection can miss content; inspect the output page by page.
To report a problem, share the tool name, browser, steps and a non-personal sample. Do not email confidential documents. Contact PDF168