Accessibility · official-source review · reviewed 2026-10-10
A deck ships with alt text on the easy images and gaps on the rest.
Turn image counts into the missing alt-text count and a coverage percent for the deck.
Anyone preparing a slide deck for readers who use screen readers.
Use the source document or official route that applies to your situation. This guide does not contact another person or verify external information.
Count all images on the slides. Include logos, charts, and background photos.
Mark images that add no information as decorative. They need no alt text.
Count the meaningful images that already carry alt text.
Write alt text for the missing images first. Describe the information, not the picture.
Rerun the count after each pass. The coverage percent shows when the deck is ready.
A deck holds 24 images, 6 marked decorative, and 12 with alt text. The count of images that need alt text is 18, and 6 are still missing.
Use your own source and details. The example is not a record about a real person or organization.
World Wide Web Consortium, Web Accessibility Initiative · reviewed 2026-10-10
What this source supports: WAI's decision tree asks authors to decide whether an image is decorative, functional, or informative before writing alt text.
Source limit: Context changes the right alt text. Test with a screen reader for your own page.
These sources support the statements above. They do not show that every person needs this guide. They do not show a specific result.
This guide counts coverage from your own audit. It does not write alt text or judge image meaning.
Context changes the right alt text. Test with a screen reader for your own page.
Use current instructions from the responsible organization. This guide is a planning aid, not an official decision or a substitute for qualified advice.
Turn image counts into the missing alt-text count and a coverage percent for the deck.
This App counts coverage from the numbers you enter. It does not write alt text or judge image meaning.
You enter every number yourself. The sources support the method and the limits. They do not produce a result for your specific case. Keep the original documents next to the sheet you build.
The App computes the worked example with your own numbers, in your browser.
APP 1
Turn image counts into the missing alt-text count and a coverage percent for the deck.
Free · no account · no upload
Open Slide Alt-Text Coverage CheckThe App runs in this browser. It does not send or save entries. Copy, download, or print only when you choose.
This guide uses short, direct instructions as an ASD-STE100-style writing target. It is not a formal certification.
Companion App: Slide Alt-Text Coverage Check. It runs in this browser and does not upload your entries.
This guide is edited for clarity and checked against the sources it links. It is not a substitute for official instructions or qualified advice. A linked source does not show that every person needs this guide.