Hear your own post: checking your alt text with the screen reader already on your computer

You can check your alt text in about five minutes with software you already own. Windows includes a screen reader called Narrator, and every Mac includes one called VoiceOver. Turn one on, open your published post, and listen to what a blind or low-vision reader hears in place of your image. Alt text that looks fine on screen often sounds wrong out loud: padded, repetitive, or too long to follow.

Think of it as proofreading by ear. If you are new to the idea, start with why alt text matters; if you already write it, this is the fastest way to find out whether it works.

Turn the screen reader on

On Windows, press Windows logo key + Ctrl + Enter to start Narrator and the same keys to stop it, as described in Microsoft’s Narrator guide. On a Mac, press Command-F5 to turn VoiceOver on or off, per Apple’s VoiceOver guide. Turn your volume up, because both will talk a lot. In Narrator, pressing the Ctrl key stops it mid-sentence, which you will want early and often.

Jump straight to the images

Listening to a whole page is slow. Instead, open your live post in a browser and move between images. In Narrator, scan mode turns on automatically in Edge, Chrome, and Firefox, and G jumps to the next graphic or image while Shift+G goes back, according to Microsoft’s page on Narrator’s scan mode. VoiceOver has its own commands for moving around a page, which Apple documents in the same guide.

What to listen for

Four things are worth noting as you go. First, does the description say what the image is for, not just what is in it? Second, does the important part come first? Listeners can skip ahead, so lead with the point. Third, does it repeat your caption word for word? If so, trim one of them. Fourth, is it longer than it needs to be? Long is fine when the image carries information, but see the 125-character rule before you decide.

You will also hear gaps. An image with no alt text is often announced as only a generic label or a file name, which is what the example above shows, and our guide to how screen readers announce images walks through the variations. If you hear that a lot on older posts, it may be time to audit your older posts.

Let Narrator describe it, then compare

Narrator can also describe an image itself. Press Narrator + Ctrl + D, and it sends the image to Microsoft and reads back a description, or generates one on the device on a Copilot+ PC, according to Microsoft’s Narrator basics chapter. Treat that as a second opinion, not a replacement. If it names a product, a sign, or a number that your alt text left out, you have found a gap. (Why a generated description is not the same job is covered in screen readers’ AI image descriptions.)

One caution: a few minutes of listening is a spot check, not an accessibility audit. People who use screen readers every day move faster and notice different things than you will. But it is enough to catch most of the sloppy alt text before it ships.

A simple routine: draft with SnipAlt using Ctrl+Shift+A (⌘⇧A on a Mac), edit, publish, then spend two minutes listening to the live post.