For 4PDFs 0.3.1, October 2026. Dotted underline: words that are not already the app's own. Italics: what the app shows on screen.
4PDFs turns paper into PDFs you can search and copy text from. You scan a page, and the PDF keeps the picture exactly as you see it with the words underneath it, so your PDF reader can find them. The words are read on your own device.
You do not have to change anything first. Out of the box a scan is greyscale at 200 dpi on A4, with the words read, which suits most letters and bills.
4PDFs opens on two tabs, Scan and Library. The Scan button is at the top of the Scan tab, with the output choices (section 3) beneath it.
Pressing it hands you to Google's document scanner, which shows you the camera, finds the edges of the page, straightens it, and lets you crop it, rotate it, clean it up and add more pages. What you keep comes back to 4PDFs; what you discard never does.
You can also scan a photograph you already have. The scanner has its own gallery button, and a picture chosen there is straightened and cropped the same way a fresh capture is.
4PDFs asks for no camera permission and no photo permission. The scanner is the one holding the camera; 4PDFs only receives the pages you decided to keep.
While it works the status line says Scanning…, and when it is done it tells you what you got, for example Scanned 3 page(s), 412 words; PDF is 806 KiB. If you back out, it says Scan cancelled.
If the word count is 0, either OCR document was off or the page had no text the reader could make out. The picture is still there.
These cards are on the Scan tab, under the Scan button. They decide how the PDF is built. Each choice below shows its starting value in bold in the right-hand column.
Sheets turn with the capture. Passports, cards and receipts get their own size; As captured follows the pixel count at 300 dpi. A scan can choose its own page on its card.
| Choice | For |
|---|---|
| A4 (starting choice), A5, A3, Letter | Ordinary paper. The sheet turns to match the way you captured the page, so a landscape page gets a landscape sheet. |
| Passport, Card, Receipt | Small documents, at their real size rather than blown up to fill a sheet. |
| As captured | The page is whatever the picture is, measured at 300 dpi. |
Place small documents on A4 (on to start with): A passport, card or receipt at its true size on an A4 sheet, like a photocopy; off, the page is the document's own size.
Split double pages (off to start with): A landscape capture with a text-free gutter (an open book) becomes two pages. Scan the book spread as one picture and the PDF comes out with a left page and a right page, the way the book reads. A landscape capture with no clear gutter, such as a wide table, stays one page.
How each page is stored in the PDF: Greyscale (starting choice), Black & white or Colour. Greyscale and colour have a JPEG quality slider (20 to 95, starting at 60); black and white has none, because it is stored without JPEG.
Black and white makes much the smallest file and suits plain printed text; colour is largest and keeps a letterhead, a photograph or a highlighter mark.
Original, 300, 200 (starting choice), 150, 100 or 75 dpi.
It changes the picture in the PDF, not the reading of the words: OCR is performed upon the raw camera image before post processing delivers the PDF. So a smaller file does not cost you searchable text. Original keeps every pixel the camera took.
On to start with. Turned off, the words are not read at all and the PDF is a plain picture of the page: not searchable, and there is no copying text out of it. Leave it on unless that is what you want.
This one is decided when you scan. Turning it on later does not add words to a scan made without them.
Also on the Scan tab. Originals let an export rebuild the PDF with the settings above; they cost the full captures in storage until removed.
| Choice | What happens |
|---|---|
| Don't keep | The captures go as soon as the PDF is built. Least storage; the PDF is final. |
| Until exported (starting choice) | They stay while the scan waits in the library, and go after the first export that succeeds. |
| Keep | They stay until you press Remove originals on the card. |
This is the setting to understand before you change your mind about a scan. While a scan still has its originals (its card says (originals kept)), exporting it builds the PDF again whenever the output choices, or the card's own page size, have changed since it was made. Once the originals are gone, the PDF is exported exactly as it was built: changing the choices, or the card's page size, no longer alters it.
With the starting choice, that means you can change page size, image or resolution freely until the first export. To keep that freedom after exporting, choose Keep.
Every scan waits on the Library tab until you discard it. Exporting saves a copy; the scan stays in the library afterwards. Before your first scan it says No scans yet. Tap Scan to capture a document.
Each scan is a card showing its file name and the date and time of the scan, then a line like 3 page(s), 412 words, 806 KiB as Greyscale q60, 200 dpi, A4: the pages, the words read, the size of the PDF and the choices it was built with. If the originals were kept it adds (originals kept). Beneath that are the first words of the text, so you can tell scans apart.
The status line counts them: 4 scan(s) in the library.
Each card carries its own buttons. The same actions are in a menu when you right-click the card or long-press it.
| Action | What it does |
|---|---|
| File name | The name the PDF will be saved under; each scan has its own. Pressing Done on the keyboard saves the name and goes straight to Export PDF. |
| Export PDF | Opens the system file picker with Choose where to save the PDF. Save it in any folder the picker reaches: internal storage, a memory card, a USB drive, or a cloud drive's folder. When it is done: Saved 806 KiB as letter.pdf. |
| Page: … | The page size for this scan alone. As in Settings follows the Page size card on the Scan tab; anything else overrides it for this one scan. It takes effect when you export, and only while the scan has its originals (section 4). |
| Discard | Removes the scan from the library at once, the PDF and any originals with it. It does not ask first, and a PDF you have already exported is not touched. It says Discarded. |
| Save originals… | Shown only while the scan has its originals. Copies the captures and their OCR JSON, as they came from the scanner, into a folder you choose. |
| Remove originals | Shown only while the scan has its originals. Deletes them and keeps the PDF, which is then final. The space comes back. |
The gear at the top right opens Settings, in two tabs, Storage and Look. The back arrow at the top left returns to the scans.
Scans wait here until exported. A folder of your choice can be one a sync app mirrors; the app's folder on a card or drive is private to it.
Choose Internal storage (starting choice), Removable storage, or a folder of your own with Choose folder…. Changing it moves every scan already there, and each one is copied, read back and checked before the old copy is removed: Moving the library to … then Moved 4 scan(s) to …. If the move cannot be done, nothing is lost: Library stays where it is: …
If the card or drive you chose is not plugged in, the app says … is not present and shows the internal library until it comes back. Your scans on the card are not affected.
Every scan's captures and OCR JSON, as they came from the scanner, for other tools to work on (for example straightening book pages).
It starts as Not copied. Choose a folder and every scan from then on is copied there as well: Raw captures will be copied to … Stop ends it. Most people never need this.
The app follows your wallpaper's colours unless you choose its own. Turn on Use the app's own colours to keep it looking the same whatever your wallpaper does.
Scans wait in the library, so you can scan with the phone in your hand and name and export them later at the desk. The library and the status line carry over when the app moves between the phone and the DeX screen.
| Key | What it does |
|---|---|
| Ctrl+N | Scan |
| Ctrl+E | Export the most recent scan |
| Ctrl+, | Open Settings, or close them |
| Escape | Close Settings |
Right-click a card for its actions (section 6), or right-click the background for Scan and Settings.
Long-press the 4PDFs icon and you get three shortcuts:
| Shortcut | What it does |
|---|---|
| Scan | Scan a document |
| Library | Open the scan library |
| Settings | Open 4PDFs settings |
Any of them can be dragged onto a home screen, or picked up by another app that asks for a shortcut. When one does, 4PDFs shows Choose a 4PDFs action: The shortcut you pick opens 4PDFs and does this.
| Message | What it means |
|---|---|
| The document scanner is not available: … | Google Play services could not start the scanner. It fetches the scanner the first time you use it, so this can mean the download has not finished. Try again in a minute. |
| Could not build the PDF: … | The pages could not be made into a scan, and no card was added. Scan again. |
| Export cancelled | You closed the file picker. Nothing was saved and the scan is still in the library. |
| Export failed: … | The PDF was not saved. The scan is still in the library, so try again. The picker may have left an empty file under the name you chose; delete it. |
| No file picker available: … | The device has no app for choosing where to save files. |
| This scan has no originals | There is nothing to save or remove: the originals have already gone. |
| Could not write to … | Copying originals or raw captures to the folder you chose failed. The scan itself is untouched. |
| … is not present | The card or drive holding the library is not plugged in. See section 7. |
| Library stays where it is: … | The move did not happen, and your scans are untouched. |
All the image work, the reading of the words and the building of the PDF happen on your device.
4PDFs does not have the internet permission, so it cannot send your documents anywhere.
Reading the words needs no download: the model is inside the app.
Scanning uses Google Play services, which is where the document scanner comes from, so 4PDFs needs a device that has Play services. Play services fetches the scanner itself the first time you scan. That is the one part of 4PDFs that is not the app alone, and it is why this page does not tell you 4PDFs is entirely offline.
There is no account, no advertising and no analytics.
See the 4PDFs privacy policy.
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