How to scan a QR code on a computer

The quickest route: a browser scanner

Computers do not have a Camera-app-with-a-banner flow the way phones do, but they do not need one. Open a browser-based scanner and give it the code one of three ways:

• Upload or drag in an image — a screenshot, a saved PNG, a photo from your phone.
• Paste an image straight from the clipboard.
• Use the webcam and hold the code up to it.

A well-built scanner runs entirely client-side: the decoding happens in your browser's own JavaScript, the image never leaves your machine, and nothing is installed. It also shows you the decoded text rather than blindly opening it — exactly what you want when checking a suspicious code. The mechanics of how in-browser decoding works are on the browser scanning page.

What each operating system gives you natively

OS	Built-in QR scanning
Windows	The Camera app includes a barcode mode in recent versions — webcam only, no image files. Details: scanning on Windows
macOS	None. Preview and Quick Look cannot decode a code. Details: scanning on a Mac
Linux	Nothing in the desktop shells; zbarimg on the command line is the standard tool. Details: scanning on Linux

That table is why the browser route wins: it is the only method that behaves identically on all three platforms and handles both image files and the webcam.

The drag-a-screenshot flow

The most common desktop case is a QR code on the screen — in an email, a PDF, a slide, a web page. The camera flow is useless there; the screenshot flow takes seconds:

1. Screenshot the code (Windows: Win+Shift+S, macOS: Cmd+Shift+4, Linux: your screenshot tool).
2. Drag the image into the scanner page, or paste it.
3. Read the decoded text, then open it if it looks right.

Cropping is unnecessary as long as the code is sharp — decoders locate the code within a larger image on their own.

Last resort: point your phone at the screen

If a phone is within reach, its camera will read a code off your monitor. It works, but monitors add glare and refresh artefacts, so raise the screen brightness and hold the phone square-on. The failure modes of this route have their own page.

Do not install a desktop scanner app

For a one-off scan, a downloaded "QR reader" utility is the worst option on the table: most are ad-supported, several phone home with whatever they decode, and none of them do anything a client-side web scanner cannot. The exception is genuine bulk work — warehouse-style scanning stations — which is better served by hardware scanners.

FAQ

Can I scan a QR code without a phone?

Yes. Upload a screenshot or image of the code to a browser-based scanner, or hold the code up to your webcam. The decoding runs in the browser itself, so nothing is installed and the image is not uploaded to a server.

How do I scan a QR code that is on my screen?

Screenshot it — Win+Shift+S on Windows, Cmd+Shift+4 on macOS — then drag the screenshot into a browser-based scanner. The decoder finds the code inside the image, so precise cropping is not required.

Does Windows or macOS have a built-in QR scanner?

Windows has a barcode mode in recent versions of the Camera app, webcam only. macOS has nothing built in — Preview and Quick Look cannot decode QR codes. On both, a browser scanner is the practical answer.

Is it safe to use an online QR scanner?

Use one that decodes client-side, meaning the image is processed in your browser and never uploaded. It should show the decoded text first rather than opening the link automatically, so you can read the destination before visiting it.