A flatbed scanner produces one image per page, leaving you with a folder of files and a portal that wants a single PDF. This combines them in order, cleans them up, and produces one document.
Your images never leave your device. They are read and processed by your browser and written into a PDF in memory. Nothing is uploaded.
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Result
Fill in the fields above and your result will appear here.
What the Scan to PDF does
The enhancement is optional but usually worth applying — even a proper scanner leaves a grey cast when the lid does not close flat, and the contrast adjustment fixes it. Set the mode to colour with contrast at zero to combine the images unchanged.
Order is set in the file list before conversion. Scanner filenames usually sort correctly, but check — page 10 often sorts before page 2.
How to use this tool
- Add all the scanned images at once.
- Check the order carefully. Filenames like page1, page10, page2 sort in the wrong order.
- Choose a processing mode, or set colour with zero contrast to leave the images untouched.
- Set the page size — A4 unless the scans are a different size.
- Press Combine into PDF.
How pages are assembled
For each image, in list order:
1. Apply the chosen enhancement.
2. Scale to fit the page inside the margin,
preserving proportions.
3. Add as the next page.
Pages out = number of images added
Orientation follows each image: a landscape scan gets a
landscape page, so mixed scans stay correctly oriented.
Worked example
Example: a scanned 10-page document
| Input | 10 JPGs from a flatbed scanner, 18 MB total |
| Mode | greyscale, contrast 40 |
| Output | 10-page A4 PDF, about 2.4 MB |
The size reduction comes from greyscale and JPEG re-encoding. Colour scans of text documents are far larger than they need to be.
What your result means
Page order comes from the file list, not from filenames. Check it before combining.
Orientation follows each image, so a mixed batch of portrait and landscape scans stays correct.
Set colour mode with zero contrast if you want the images combined without any processing.
Important considerations
- Filename sorting is the usual cause of out-of-order pages. Rename with leading zeros — page01, page02 — or fix the order in the list.
- Scan at 200–300 DPI for documents. Higher resolutions produce huge files with no benefit for text.
- Greyscale roughly halves the file size of a text document compared with colour, with no loss of legibility.
- For a searchable PDF, run the result through OCR.
- To combine existing PDFs rather than images, use the merge tool.
Limitations of this tool
- Images are capped at 2400–3000 pixels on the longest side to keep memory use manageable on phones.
- Photographs are embedded as JPEG, so PNG transparency is flattened onto white.
- Perspective distortion cannot be corrected — photograph the page square-on for the best result.
- Images only — to combine PDF files, use the merge tool.
- Automatic deskewing and edge detection are not available.
Frequently asked questions
My pages came out in the wrong order — why?
Filenames sort as text, so page10 comes before page2. Fix the order with the arrows in the file list, or rename the files with leading zeros before adding them.
What resolution should I scan at?
200–300 DPI for documents. Higher gives very large files with no readability gain; lower starts to blur small text.
Should I scan in colour or greyscale?
Greyscale for ordinary text documents — the file is roughly half the size and just as readable. Colour only when a seal, stamp or highlighting matters.
How is this different from merge PDF?
This combines images into a PDF. Merge combines existing PDF files. Use this for scans, merge for documents.