Scan to PDF

How do I scan a document?

You need a scanner or a phone camera. With a scanner, place the page face down on the glass and scan it from your computer's scan app. With a phone, photograph the page on a darker, flat surface; this tool then finds the edges, straightens the page and saves it as a PDF.

1. On a phone, press Take a photo of a page. On any device, Choose photos adds pictures you already have (JPG, PNG, WebP or iPhone HEIC).
2. Check the corners. The tool marks the page it found; drag any corner that is off. A magnifier shows the spot under your finger.
3. Add the next page with + Photograph the next page or + Add photos, and drag the cards into order.
4. Pick a look (Enhanced, Original color, Grayscale or Black and white), the page size and the quality.
5. Press Make PDF, then Download. To search the text later, continue in OCR PDF.

How do I scan a document with a scanner or printer?

Put the page face down on the scanner glass, or in the document feeder, and close the lid. On Windows, open the Scan app, pick the scanner, the file type and a folder, then press Scan. On a Mac, open Printers and Scanners in System Settings, select the scanner and click Open Scanner.

The Windows Scan app saves JPEG, PNG, TIFF or Bitmap files, not PDF, and puts them in the Pictures/Scans folder unless you choose another one, as Microsoft's guide Install and use a scanner in Windows explains. To turn those pictures into one PDF, add them here and press Whole photo on each page, since a flatbed scan is already flat, or use JPG to PDF.

On a Mac, choosing PDF in the Format menu saves a PDF straight away, and Apple's guide Scan images or documents using a scanner and your Mac shows the option to add text recognition at the same time.

How do I scan a document with my phone, on iPhone or Android?

Use the camera. On this page, tap Take a photo of a page, photograph the page, check the corners and add the next page; then tap Make PDF. iPhones can also scan in the Notes app and Android phones in the Google Drive app, both free, and our phone scanning guide gives the steps for each.

Apple describes the Notes and Files scanner in How to scan documents on your iPhone or iPad, and Google describes the Drive scanner in Scan documents with Google Drive. Step by step instructions for both are in How to Scan a Document on iPhone and Android. This page works in Safari and Chrome on either phone, and it also takes photos you took earlier, including iPhone HEIC photos.

How to scan a document on iPhone

Open the Notes app, tap the Attachment button, choose Scan Documents and hold the phone over the page. Auto mode captures it, then you drag the corners to fit, tap Keep Scan and tap Done. The Files app can scan straight to a folder. The iPhone scanning guide lists every step and Apple's instructions.

Step by step, with the Files app route and tips, in How to Scan a Document on iPhone and Android.

How does the tool find the edges of the page?

It shrinks the photo to about 480 pixels, blurs it, and separates the bright paper from the darker background with Otsu's method. It then takes the largest bright area, picks the four corners that enclose the most of it, and moves each side onto the strongest edge nearby before joining them.

From those four corners the tool works out a perspective transform (a homography) and redraws the page as a flat rectangle, blending the four nearest pixels for each point. The page width is the average of the top and bottom edges, and the height the average of the two sides, so a letter page keeps a letter shape. The corners are pulled half a percent toward the middle first, so a corner set a pixel outside the paper leaves no line of desk along the edge.

If the page and the surface under it are both light, there is no clear edge to find. The tool then uses the whole photo and says so, and you drag the four corners onto the page.

Which look should I choose for a scanned document?

Black and white suits printed text and forms: it gives the crispest letters and the smallest file. Enhanced turns the paper white but keeps colored ink, stamps and highlights. Grayscale keeps soft shading such as pencil, and Original color keeps the photo as taken, which suits pictures and colored paper.

Black and white compares each pixel with the average of the square around it (the Bradley and Roth adaptive threshold), so a shadow across the page does not turn into a black patch. JPEG codes sharp black edges poorly: saved as JPEG, the same black and white page made a 369 KB PDF at Standard, against 55 KB as lossless PNG, which is what the tool uses. Enhanced measures the paper color in small blocks and divides it out, which also removes uneven light.

What resolution should I scan documents at?

Use 300 dpi for pages you will print, keep or run through OCR, and 200 dpi for everyday documents and email. 150 dpi still reads well on screen and suits strict upload limits. In this tool, High, Standard and Smaller file give those three resolutions, measured on an 11 inch page.

Small print is where resolution shows. In our OCR test, 6 point text was read 93.3% correctly at 150 dpi and 100% at 300 dpi, while 11 point text was read 100% correctly at both. A phone photo sets the upper limit: in our test the page filled most of a 12 megapixel photo and came out at about 288 pixels per inch.

• High (300 dpi, JPEG 90%): pages up to 3300 pixels on the long side.
• Standard (200 dpi, JPEG 75%): pages up to 2200 pixels on the long side.
• Smaller file (150 dpi, JPEG 60%): pages up to 1650 pixels on the long side.

For a PDF that must fit an upload limit, see Compress PDF after scanning.

How do I make a scanned PDF searchable?

A scan is a picture of the page, so search and copy find nothing yet. After you save, press OCR PDF under Or continue in. It reads the words in your browser and adds them as invisible text over the picture, so you can search, select and copy the text.

OCR PDF runs on your device like this tool, so the scan stays private. Our guide Searchable vs Scanned PDF shows how to tell which kind of PDF you have.

How do I get a clean scan with a phone camera?

Lay the page flat on a darker surface, such as a wooden table, in even light. Hold the phone straight above it so the whole page fits with a strip of background on every side, and keep your shadow off the paper. Tap the screen to focus on the text before you take the photo.

• Contrast: the edges are found from the step between light paper and a darker surface. A white page on a white desk gives nothing to find.
• Straight above: the flattening fixes tilt, but a steep angle leaves the far half of the page with fewer pixels, so its text comes out softer.
• No flash glare: a bright reflection becomes a white spot with no text in it, and no filter can bring the text back.
• Flat paper: the tool straightens perspective, not curves, so press folded or curled pages flat.