What is On-Page SEO? The Complete Guide
On-page SEO covers the elements you control on each page: title tags, headings, content, images, and schema. Here is what each one does and how to audit them.
16 May 2026 · 7 min read
On-page SEO is the practice of optimising the elements you control directly on a webpage to help search engines understand the page and rank it for relevant queries. It covers everything from your title tag and headings to your body copy, internal links, images, and structured data.
On-page SEO is distinct from technical SEO, which deals with crawlability and indexability, and from off-page SEO, which covers backlinks and external signals. On-page SEO is what you write and how you structure it. It is the most direct lever you have over how a page performs in search.
What are the core elements of on-page SEO?
Title tag
The title tag is the HTML element that defines the name of a page. It appears in the browser tab, in search engine results pages, and when pages are shared on social media. It is the single most important on-page element for telling search engines and users what the page is about.
Every page needs a unique, descriptive title tag that includes the primary keyword, ideally near the start. Keep it under 60 characters to avoid truncation in SERPs. See the full guide to title tags.
Meta description
The meta description is the short summary displayed beneath a title tag in search results. It is not a direct ranking factor, but it influences click-through rate, and Google uses it as a signal when generating AI Overviews.
Write meta descriptions between 150 and 160 characters. Include the primary keyword and a clear reason to click. Each page should have a unique meta description. See how to write a meta description.
H1 and heading hierarchy
The H1 is the main heading on the page. Every page should have exactly one H1, and it should clearly describe the topic. Think of it as the page's title as seen by the reader, not just the search engine.
Below the H1, use H2s for main sections and H3s for sub-points within those sections. This hierarchy helps search engines parse the structure of your content and helps readers scan the page. Never skip heading levels for visual reasons alone. H4 through H6 exist for deeply nested content but are rarely needed for most articles.
Missing or duplicate H1s are one of the most common on-page issues found during a crawl.
URL structure
A clean, descriptive URL helps both users and search engines understand what a page is about before they visit it. Use lowercase letters, hyphens (not underscores), and include the primary keyword. Avoid unnecessary parameters, dates in most cases, and lengthy strings of numbers.
A URL like /learn/what-is-on-page-seo is clear. A URL like /page?id=4281&ref=blog tells no one anything. See the full guide on how to write SEO-friendly URLs.
Body content
The body of the page is where you demonstrate relevance to the search query and depth of coverage on the topic.
A few principles:
- Place the primary keyword naturally in the first 100 words
- Use semantically related terms throughout (not keyword stuffing, but genuine coverage of the topic)
- Match the depth of your content to what the query requires: a transactional query needs a clear, fast answer; an informational query may warrant a thorough guide
- Use short paragraphs, numbered lists, and tables to make content easy to scan
- Aim for 1,500 to 2,500 words for competitive informational queries, but let search intent dictate length, not an arbitrary target
Internal linking
Internal links connect your pages to each other. They pass authority between pages, help search engines discover new content, and guide users through your site.
Use descriptive anchor text, not "click here" or "read more." Link from high-authority pages to pages you want to rank. Build topical clusters: a pillar page covering a broad topic supported by cluster articles on sub-topics, each linking back to the pillar.
Thin internal link structures leave pages isolated and underperforming. See how to audit internal links.
Images
Every image on a page should have descriptive alt text that explains what the image shows. Alt text is how search engines understand images, and it is essential for accessibility.
File names also matter. dog-food-ingredients.jpg is better than IMG_0042.jpg. Compress images before uploading: unoptimised images are the leading cause of slow page loads, which affect both rankings and user experience.
Schema markup
Schema markup is structured data added to a page's HTML that explicitly tells search engines what the content represents. An article, a product, a FAQ, a recipe: schema helps search engines categorise and extract your content accurately.
FAQPage schema, in particular, can result in your content being pulled directly into Google AI Overviews and other AI search surfaces. See what is schema markup.
Open Graph tags
Open Graph tags control how your page appears when shared on social platforms: the title, description, and image. They are not a direct ranking factor, but well-crafted Open Graph tags increase click-through when content is shared, which drives traffic and indirect signals.
See what is Open Graph.
What is search intent, and why does it matter for on-page SEO?
Search intent is the underlying reason behind a query. Google's primary job is to match results to intent, and your page needs to match that intent before anything else matters.
There are four types of search intent:
| Intent type | What the user wants | Example query |
|---|---|---|
| Informational | To learn something | "what is on-page SEO" |
| Navigational | To reach a specific site or page | "Crawly download" |
| Commercial | To research before buying | "best SEO crawler for Mac" |
| Transactional | To complete a purchase or action | "download SEO crawler free" |
If your page targets an informational query but reads like a sales page, it will not rank. If it targets a transactional query but buries the call to action under 2,000 words of background reading, it will underperform.
Match the format of your content to the intent. Informational queries typically reward in-depth guides with clear headings. Transactional queries reward simple, direct pages with a clear action to take.
How is on-page SEO different from technical and off-page SEO?
Understanding the three pillars helps you prioritise your work:
On-page SEO covers the content and elements on the page itself: titles, headings, body copy, images, internal links, schema, and Open Graph. This is what you write and how you structure it.
Technical SEO covers the infrastructure that allows search engines to find and index your pages: crawlability, indexability, site speed, Core Web Vitals, HTTPS, and structured data implementation. Without a working technical foundation, on-page SEO has no surface to land on. See what is technical SEO.
Off-page SEO covers signals that originate outside your site: backlinks, brand mentions, and third-party authority signals. These tell search engines that other credible sources trust your content.
The correct order of operations is: fix technical issues first, then optimise on-page elements, then build off-page authority. On-page work done on a site with crawling or indexing problems is largely wasted.
How do you audit on-page SEO?
A proper on-page audit reviews each element systematically across every page, not just a handful you happen to remember. The most efficient way to do this is with a site crawl.
Work through the following for each page:
- Title tag: present, unique, under 60 characters, contains primary keyword
- Meta description: present, unique, under 160 characters, matches page intent
- H1: exactly one per page, clearly describes the topic
- Heading hierarchy: logical H2 and H3 structure, no skipped levels
- URL: clean, descriptive, no unnecessary parameters
- Body content: covers the topic with appropriate depth, keyword placed naturally
- Images: all have descriptive alt text, files are compressed
- Internal links: page links out to relevant content, receives links from elsewhere on the site
- Schema: appropriate schema types implemented and valid
- Open Graph: title, description, and image set correctly
For large sites, reviewing hundreds or thousands of pages manually is not practical. A crawler surfaces every page, flags missing or duplicate titles, missing H1s, meta descriptions over 160 characters, and missing alt text, giving you a complete list of issues to work through.
After fixes, re-crawl to confirm the issues are resolved and to catch any new ones introduced during the update.
What makes on-page SEO harder in 2026?
On-page optimisation now serves two audiences: the Google algorithm and AI systems. Google AI Overviews, ChatGPT Search, Perplexity, and Claude all extract and cite content directly, and they reward the same signals: direct answers early in each section, clear heading structure, schema markup, and verifiable claims from named authors.
The practical implication is that well-structured on-page SEO is no longer just about ranking in traditional search results. Pages that are well-optimised for on-page SEO are also better positioned to be cited in AI-generated answers, which now appear before organic results for a growing share of queries.
Crawly crawls your entire site and flags missing title tags, missing H1s, duplicate titles, meta descriptions over 160 characters, and missing alt text in a single crawl, with no page cap and no subscription required. Download Crawly to run a free on-page audit across every page on your site.