Scan a Document Online

A real document scanner is a wonderful thing — and most of the time you don’t have one nearby. What you do have is a camera in your pocket. The catch is that a phone photo of a page never looks like a scan: it’s shot at an angle, the lighting is uneven, the corners are crooked, and the desk shows around the edges. This guide explains how to turn that casual snapshot into a clean, square-on, scanner-style document — and how to do it for free, right in your browser, with the tool at the top of this page.

What “scanning” actually means

A flatbed scanner does three things a camera doesn’t: it holds the page perfectly flat and parallel, it lights it evenly, and it crops to the page edges. To fake a scan from a photo, you reproduce those three steps in software:

1. Find the page. Locate the four corners of the document within the photo.
2. Correct the perspective. Remap the angled, trapezoid-shaped page into a flat rectangle — this is the single most important step.
3. Enhance. Even out the lighting and boost contrast so text is crisp and the paper reads white.

Do those three things and an ordinary photo becomes something you’d be happy to email, print, or file.

Step 1 — Add your photo

Drag a photo of the document onto the tool, click to choose a file, or paste an image straight from your clipboard. Anything your browser can open works — JPG, PNG, WebP, and the first frame of a GIF or BMP. For the best result, take the photo straight down over the page on a surface that contrasts with the paper, and fill most of the frame with the document.

The image is decoded and shown on the canvas, with a starting selection box inset slightly from the edges. Everything from here happens on your device — there is nothing to upload and wait for.

Step 2 — Set the four corners

This is where the scan is made or broken. You have two ways to place the corners:

• Auto-detect edges. Tap the button and the tool analyses the image — converting it to grayscale, blurring out paper texture, finding edges, and looking for the largest four-sided shape. When it finds the page, the four handles snap to its corners. The edge-detection engine (a computer-vision library) loads from a CDN the first time you use it, so the very first detection takes a moment; after that it’s instant.
• Drag them by hand. Grab any corner handle and move it onto the true corner of the document. On a phone the handles are sized for a fingertip. Manual placement always works, even if auto-detect can’t load or doesn’t find a clean outline — so the tool is never stuck.

Step 3 — How perspective correction works

When the four corners are set, the tool performs a perspective transform (also called a four-point warp or homography). In plain terms: it works out the exact stretch that maps your four corner points onto the four corners of a clean rectangle, then redraws every pixel through that mapping. The leaning trapezoid becomes a flat, straight-on page, and the desk around it is cropped away.

This is the same maths behind professional scanner apps. It’s also what people mean by deskewing a document — removing the slant so lines of text sit truly horizontal. It works on more than paper, too: whiteboards, slides, posters, paintings, and signage all benefit from the same correction.

The output size is chosen from the lengths of your quadrilateral’s edges, so the scan keeps the document’s real resolution rather than being blown up or crushed.

Step 4 — Enhance the page

A raw perspective-corrected photo still carries the original lighting. The enhance filter fixes that. You have four options:

• Magic — the default “scanner” look: it lifts the whites and deepens the darks so a slightly grey, shadowed page reads clean and bright while keeping colour.
• Black & White — binarises the page to pure black text on white paper, using the image’s own brightness to pick the threshold. This is the crispest option for text and the best input for OCR.
• Grayscale — a neutral grey conversion, good for photos within a document.
• Original — no adjustment, if your photo was already evenly lit.

Tick Preview corrected scan at any time to see the warped, enhanced result in place before you commit.

Step 5 — Save as PDF or PNG

Finally, choose your output:

• PDF is the natural format for a document. Pick A4 or US Letter to place the scan neatly on a standard page with margins, or Fit to make the PDF exactly the size of the scan. A quality slider controls the embedded image size so you can balance sharpness against file size.
• PNG gives you just the corrected image, ideal if you’re going to drop it into another document or post it online.

Click Download and the file is saved straight to your device.

Tips for a great scan

• Light evenly. Avoid a hard shadow falling across the page; soft, even light makes the Black & White and Magic filters look their best.
• Contrast the background. A dark desk under white paper helps auto-detect lock onto the edges.
• Hold steady and square. The closer you are to shooting straight down, the less correction is needed and the sharper the result.
• Deskew before OCR. If you’ll run text recognition, scan in Black & White first — level, high-contrast pages are read far more accurately.

Privacy

The scan is created in your browser using your device’s own processor, so the finished file is produced locally. How any data associated with the tool is handled is described in our privacy policy. For highly sensitive paperwork, an offline desktop tool remains the most private option of all.

Whether you’re digitising a receipt for an expense report, turning a signed form into a PDF, or capturing a whiteboard before it’s wiped, the steps are the same: add the photo, set the corners, enhance, and download. Give the scanner at the top of the page a try.