Heading Tags and Alt Text: The SEO & Accessibility Guide
Headings and alt text are small pieces of HTML that do two jobs at once: they help search engines understand your content and make it usable for people with screen readers. Here's how to get both right.
Use one H1 that states the page's topic, H2s for main sections and H3s beneath them without skipping levels, and write headings as descriptive labels. Give every meaningful image short, descriptive alt text (under about 125 characters), use alt="" for decorative images, and never use file names as alt text.
How to structure H1–H6 headings
Think of headings as the page's table of contents. One H1 names the topic. H2s divide it into main sections. H3s break down an H2, and so on. Don't jump from H2 to H4 — screen-reader users navigate by heading level and the outline breaks.
Google has said it handles multiple H1s and that headings aren't a strict ranking rule — but descriptive headings help it understand sections, and they're sometimes used for featured snippets and jump links. Check any page's outline with the Heading Analyzer, and audit H1s across many pages with the H1 Checker.
Common heading mistakes
Styling text with heading tags because they look big. Wrapping logos or icons in H1s on every page. Empty headings left by page builders. Vague headings like “Overview” or “More” that tell readers nothing. Keyword-stuffed headings that read unnaturally.
How to write good alt text
Describe what the image shows and why it's there, in one short sentence: “Bar chart showing mobile traffic rising from 40% to 65% in 2025” rather than “chart”. Skip “image of” — screen readers already announce it's an image. Include a keyword only when it naturally describes the image.
Alt text is also how search engines understand images, which is how they rank in Google Images.
Decorative images and alt=""
Images that add no information — dividers, background flourishes, an icon beside text that says the same thing — should have an empty alt attribute (alt=""), so screen readers skip them. Leaving out the alt attribute entirely is different and always a problem: some screen readers then read the file name aloud.
Find missing, file-name and overly long alt text with the Image Alt Text Checker.
Try Free Web Tools Mentioned in This Guide
Heading Analyzer
Map a page's H1–H6 outline and find missing H1s, skipped levels and empty headings.
H1 Checker
Bulk-check the H1 tag and H1–H6 counts for up to 10 URLs at once.
Image Alt Text Checker
Find images with missing, empty, file-name or overly long alt text on any page.
SEO Checker
Audit any page's SEO — meta tags, headings, content, images, links, schema and technical health.
Frequently Asked Questions
Can I use more than one H1?↓
It's valid HTML and Google copes with it, but a single, clear H1 is still the recommended structure.
Does alt text help SEO?↓
Yes — it helps images rank in image search and helps search engines understand the page. More importantly, it makes images accessible.
How long should alt text be?↓
Usually under 125 characters — one concise, descriptive sentence.