Scan a document to PDF
Photograph each page with your phone. The corners are found, the page is flattened and cleaned up, and every page goes into one PDF. Nothing is uploaded.
One photo per page, all four corners in view · or drop photos here · opened on this device, never uploaded
- Dark, plain surfaceWhite paper on a wooden table or dark floor lets the corners be found.
- All four corners in viewHold the phone above the page; a tilt is straightened.
- Even lightNo flash. Black & white removes a soft shadow, not a hard one.
Flattened page
Pages
Tap a page to edit it. Drag a page to put it somewhere else.
Clean up (all pages)
Save
Size: –
Need the words as text? Save the pages as JPG and open them in Image to Text to copy the text out.
Privacy: your pages are processed in your browser and never uploaded. The photos are opened, flattened and written into the PDF inside this page. The saved files are drawn fresh, so the photo's EXIF data (camera, time, GPS location) is not carried over, and the PDF has no title, author, producer or date. Nothing is kept after you close the tab.
How to scan a document with your phone
- Lay the page flat on a darker surface in even light, such as a wooden table or a dark floor. White paper on a white desk gives the corner finder nothing to see.
- Tap Take photos and photograph the page from above with all four corners in the picture. A slight angle is fine; it is corrected. On a computer, use Open photos or drop pictures onto the page.
- Check the corners. The frame shows what was found. Drag any corner that missed; a magnifier shows the spot under your finger. Rotate turns a page that came out sideways.
- Pick a clean-up. Black & white suits typed or handwritten pages and removes shadows; Greyscale keeps pencil and stamps soft; Colour keeps photos and highlighter.
- Add the other pages with + Photo a page, drag them into order, then choose A4, Letter or Fit to image and tap Download PDF, or save each page as a JPG.
What it cannot do
- The PDF has no text layer. Each page is a picture, so you cannot search or copy its words. Use Image to Text on the JPGs to get the text out.
- Auto-corners can miss on a busy or pale background, such as a patterned tablecloth, paper on a white desk, a hard shadow across the page, or a page whose corner is out of the photo. Drag the corners onto the page by hand.
- Pages live only in this tab until you download. Close or reload it and they are gone; nothing is saved on the device or anywhere else.
- It flattens a page, it does not unbend one. The correction maps four corners to a rectangle, so a curled page or a book's curved spine stays curved.
- Pages are saved at up to 2,000 pixels on the long side, about 170 dpi on A4: sharp for text and forms, not for archive-quality photo prints. Photos larger than 2,400 pixels are reduced when opened.
- HEIC photos open only in a browser that can show them (Safari can). A photo taken through Take photos on an iPhone is normally handed over as JPG, so this only matters for HEIC files opened from Files.
How the clean-up works
Finding the corners. The photo is shrunk to 360 pixels on its long side, and the brighter half of its tones (split by Otsu's method) is taken as paper. The largest bright patch is filled in, its outline traced, and the biggest four-sided shape that fits that outline gives rough corners. Each side is then re-fitted as a straight line through the outline points along it, and the corners are where those lines cross. That is why a dark, plain background works best, and why a page that touches the photo's edge can be cut off.
Flattening. The four corners and the four corners of the flat page give eight equations for a perspective transform (a homography), solved in the page. The page's true width-to-height shape is worked out from the same four corners, treating the phone as a pinhole camera centred on the photo, so a tilted A4 sheet comes out as A4 (1 : 1.414) instead of squashed. Each output pixel is then read from the photo by blending its four nearest pixels (bilinear sampling).
Black & white. A single threshold fails on a shadowed page: the paper in the shadow is darker than the ink in the light. So the page's own paper brightness is measured everywhere first (the brightest value in each small block, spread and smoothed), and each pixel is compared with the paper around it. Ink is anything under about 74 % of its local paper; a narrow ramp keeps letter edges smooth. Brightness moves that cut-off and contrast narrows the ramp. Faint pencil can drop out; if it does, move Brightness to the left, which raises the cut-off so more of the faint marks count as ink, or use Greyscale.
Questions
How do I scan a document to PDF on an iPhone?
Open this page in Safari and tap Take photos: the back camera opens. Hold the phone straight above the page so all four corners are in the picture, take the shot and tap Use Photo. The page appears with its corners marked; drag any that missed, then tap + Photo a page for the next one. When the last page is in, choose a page size and tap Download PDF; Safari saves it to Files (Downloads) or offers to open it.
How do I scan a document to PDF on Android?
Open the page in Chrome, tap Take photos and allow the camera if asked. Take one photo per page; each one is flattened as soon as it is taken. Some Android phones offer a choice between the camera and Files: choose the camera. Download PDF saves the file to the Downloads folder, where any PDF viewer, mail app or upload form can pick it up.
Is it free, and are my pages uploaded?
It is free, with no account, no watermark and no page limit. The photos are never uploaded: they are opened, straightened and written into the PDF by your own browser, so this works for payslips, IDs and medical letters. The page counts an anonymous visit and two fixed event names (photos opened, PDF saved), never a picture, a file name or a page count.
How do I scan a document to PDF on a computer?
A desktop browser ignores the camera request, so Take photos opens the file picker instead. Photograph the pages with a phone and copy them over, or open pictures from a scanner or a webcam app, and drop them all onto the page at once. Everything else works the same, and a mouse makes the corner handles easy to place exactly.
Why can I not search or copy the text in my scanned PDF?
Each page in the PDF is a picture of the paper, with no text layer. To get the words out, save the pages as JPG and open them in Image to Text, which reads printed text in the browser and lets you copy it.
How do I make the scanned PDF smaller?
Use Black & white for text pages: the paper becomes pure white, which a JPEG stores in very few bytes. Then lower JPEG quality; the estimate under the slider shows the result before you save. Quality 60 to 70 is still sharp for text. Colour photos of a page with pictures stay larger; PDF Compressor can shrink a finished PDF further.