The H1 tag is your page's primary headline wrapped in <h1></h1> HTML code. Search engines treat it as the most important text signal on the page after your title tag, using it to understand topic relevance and whether your content matches search intent. From an SEO perspective, every page should have exactly one H1 that includes your target keyword naturally. Google's John Mueller has confirmed they can handle multiple H1s since HTML5, but singular H1s remain best practice because they create clear content hierarchy. When we audit sites in the Ottawa SEO portfolio, pages with keyword-optimized H1s consistently outrank identical content with generic headlines. Your H1 doesn't need to match your title tag word-for-word. The title tag is for search results and browser tabs (50-60 characters), while the H1 is the actual headline visitors see (no strict limit, but keep it under 70 characters for scannability). For a page targeting "commercial locksmith Toronto," your title might be "Commercial Locksmith Toronto | 24/7 Emergency Service" while your H1 could be "Commercial Locksmith Services in Toronto." Common H1 mistakes we fix during site audits: - Missing H1 entirely or hiding it with CSS - Using your logo image as the H1 without proper alt text - Stuffing multiple keywords awkwardly - Identical H1s across different pages - Burying the H1 below the fold where users never see it The H1 should match user intent for the keyword you're targeting. If someone searches "how to change a tire," they want instructions, not "Professional Tire Services." Mismatched intent kills rankings even with perfect technical setup. At Ottawa SEO, we treat H1 optimization as foundational work in every on-page audit. It takes 30 seconds to fix and often correlates with 15-30% traffic improvements when part of broader on-page cleanup. Not because the H1 alone is magic, but because sites that botch their H1s usually have deeper structural issues worth addressing.