Your website’s HTML foundation might be sabotaging your search rankings without you knowing it. While Google’s algorithms have evolved dramatically over the past decade, many websites still carry legacy HTML tags that not only fail to boost SEO but actively harm it. The shift in web standards from using HTML for presentation to focusing on content structure has led to CSS replacing many old HTML tags, advocating for a clean separation of content and style in web design. Relying on deprecated tags negatively affects web accessibility and SEO[1]. In this comprehensive guide, we’ll identify the specific outdated HTML tags hurting your site’s performance and show you exactly how to fix them.
Check Your Website For Outdated HTML Tags For FREE!
Why Outdated HTML Tags Matter More Than Ever in 2025
Search engines have become increasingly sophisticated at interpreting web content, but they still rely heavily on proper HTML structure to understand and rank your pages. Using proper HTML tags can have a huge positive effect on rankings, while missing or broken tags can cause pages to drop in rankings[2]. When your site uses deprecated HTML tags, you’re essentially speaking an outdated language that search engines struggle to interpret effectively.
Modern SEO isn’t just about keywords—it’s about semantic markup, user experience, and technical excellence. Outdated HTML tags create several critical problems: they slow down page load times, confuse search engine crawlers, reduce accessibility scores, and signal to Google that your site lacks technical maintenance. In 2025, well-optimized HTML tags are vital for improving search visibility, enhancing user experience, and ensuring your site ranks competitively[3].
The Most Dangerous Outdated HTML Tags Still Hurting Websites
1. The Meta Keywords Tag: A Ranking Killer
Perhaps the most notorious outdated tag is the meta keywords tag (<meta name="keywords" content="...">). Not only is the meta keywords tag ineffective for SEO, but overusing it can hurt your rankings. Stuffing your meta keywords tag with irrelevant or spammy keywords can make your site look untrustworthy to both search engines and users[4]. Google officially stopped using this tag for ranking purposes in 2009, yet millions of websites still include it.
Why it hurts your SEO: Search engines now view keyword-stuffed meta keywords as a spam signal. Sites that still use this tag, especially with excessive keywords, may face ranking penalties.
What to do: Remove the meta keywords tag entirely from your website. Focus instead on optimizing your meta descriptions and title tags with naturally integrated keywords.
2. Font Tags: The Accessibility and SEO Nightmare
The <font> tag was used to control text appearance before CSS became standard. This tag is now completely deprecated and creates multiple SEO problems. It bloats your HTML code, reduces page speed, and fails accessibility standards that Google increasingly prioritizes in rankings.
Modern alternative: Use CSS styling instead. Replace <font color="red" size="4">Text</font> with proper CSS classes like <span class="highlight">Text</span> and define styling in your CSS file.
3. Center Tags: Semantic Structure Confusion
The <center> tag centers content but provides no semantic meaning to search engines. Modern HTML requires semantic structure that helps search engines understand content hierarchy and context.
Better approach: Use CSS text-align properties or flexbox/grid layouts. Replace <center>Content</center> with proper semantic tags like <div class="centered">Content</div> styled with CSS.
4. Bold and Italic Presentation Tags
While <b> and <i> tags still work, they’re presentation-focused rather than semantic. Search engines prefer semantic alternatives that provide context about why text is emphasized.
SEO-friendly alternatives:
- Replace
<b>with<strong>for important content - Replace
<i>with<em>for emphasized text - Use
<mark>for highlighted text
Advanced Outdated Tags That Technical SEOs Miss
Frameset and Frame Tags
If your site still uses <frameset>, <frame>, or <noframes> tags, you’re likely invisible to search engines. These tags prevent proper crawling and indexing of your content.
Marquee Tags for Moving Text
The <marquee> tag creates scrolling text that’s not only deprecated but harmful to user experience and accessibility—both major ranking factors in 2025.
Table-Based Layout Tags
Using tables for layout purposes (rather than actual tabular data) creates semantic confusion and slower loading times. Modern CSS Grid and Flexbox provide superior alternatives.
How to Detect Outdated HTML Tags on Your Website
Identifying problematic tags across your entire website can be overwhelming, but several tools can help:
Free Detection Tools
W3C Markup Validator: Visit validator.w3.org to check individual pages for deprecated tags and HTML errors.
SEO Site Checkup: Their deprecated HTML tags test specifically identifies outdated tags affecting SEO[5].
Toolsaday Checker: This free tool checks if your website is using outdated, deprecated HTML tags[6].
Manual Inspection Method
For WordPress users, you can inspect your theme files directly:
- Access your WordPress admin dashboard
- Navigate to Appearance → Theme Editor
- Search theme files for deprecated tags like
<font>,<center>, and<meta name="keywords"> - Check your content for inline styling that should be moved to CSS
Step-by-Step Cleanup Process for Maximum SEO Impact
Phase 1: Critical Tag Removal
Priority 1: Remove meta keywords tags from all pages immediately. This includes:
- Header.php files in WordPress themes
- SEO plugin settings that auto-generate keywords
- Individual page/post meta keyword fields
Priority 2: Replace all font tags with CSS styling. Create a stylesheet that handles all text formatting previously done with deprecated tags.
Phase 2: Semantic Structure Improvement
Convert presentation tags to semantic alternatives:
<b>→<strong>for important content<i>→<em>for emphasis<center>→ CSS text-align or flexbox- Table layouts → CSS Grid or Flexbox
Phase 3: Modern HTML5 Implementation
Upgrade to semantic HTML5 tags that provide clear content structure:
<header>,<nav>,<main>,<article>,<section>,<aside>,<footer>- Proper heading hierarchy (H1 → H2 → H3)
- Schema markup integration for enhanced search results
Platform-Specific Solutions
WordPress Websites
WordPress users should focus on:
- Updating themes that use deprecated tags
- Checking page builders like Elementor or Divi for outdated code
- Installing plugins like HTML5 Validator to monitor code quality
- Using modern, well-coded themes that follow current HTML standards
Wix and Shopify Users
Platform users have limited control but can:
- Choose modern templates that use current HTML standards
- Avoid custom code widgets that insert deprecated tags
- Use platform-specific SEO tools properly
- Request template updates from developers if using custom themes
Measuring the SEO Impact of Your HTML Cleanup
After implementing changes, monitor these key metrics:
- Page Speed Scores: Use Google PageSpeed Insights to measure loading time improvements
- Core Web Vitals: Monitor LCP, FID, and CLS scores in Google Search Console
- Crawl Errors: Check Search Console for reduced HTML validation errors
- Ranking Changes: Track keyword positions 4-6 weeks after implementation
- Accessibility Scores: Use tools like WAVE or axe to measure accessibility improvements
Most websites see measurable improvements within 2-4 weeks of cleanup, with continued gains over the following months as search engines re-crawl and re-evaluate the improved code structure.
Key Takeaways
- Meta keywords tags actively harm SEO and should be removed immediately from all pages
- Deprecated presentation tags like <font> and <center> hurt both SEO and accessibility
- Semantic HTML5 tags provide better context to search engines than outdated alternatives
- Free validation tools can quickly identify problematic tags across your entire website
- Platform users should prioritize modern themes and avoid custom code with deprecated tags
- Regular HTML audits should be part of your ongoing SEO maintenance strategy
- Improvements typically show in rankings within 2-4 weeks of implementing fixes
Take Action: Audit Your Website Today
Don’t let outdated HTML tags continue sabotaging your search rankings. Start by running your homepage through the W3C Markup Validator to identify immediate issues. For a comprehensive SEO audit that includes HTML tag analysis, technical optimization, and competitive insights, request your free website audit today.
Our team regularly helps small business owners clean up legacy HTML issues that have been holding back their search performance for years. Many see significant ranking improvements within the first month of implementation.
Ready to dive deeper into technical SEO? Explore our complete technical SEO checklist or learn about modern HTML5 SEO best practices to stay ahead of the competition.
References
[1] Pure Code AI. (2024). “Here Are Deprecated HTML Tags and Their Alternatives.” Pure Code Blogs.
[2] SE Ranking. (2025). “13+ SEO HTML Tags You Can’t Do Without in 2025.” SE Ranking Blog.
[3] UpGrowth. (2024). “Top HTML Tags You Need to Know for SEO in 2025.” UpGrowth Digital Marketing.
[4] BrandWell. (2025). “Best Meta Tags for SEO: Boost Your Rankings in 2025.” BrandWell AI Blog.
[5] SEO Site Checkup. “Deprecated HTML Tags Test.” SEO Site Checkup Tools.
[6] Toolsaday. “Deprecated HTML Tags Checker.” Toolsaday SEO Tools.
