Headings in HTML 5

The heading elements define headings for contents such as text and images. They specify a hierarchical structure of a Web page by grouping the contents into different headings. HTML defies six levels of heading that ranges from H1 to H6. The H1 element specifies the top-level heading, which is displayed with the largest size. The H6 element specifies the lowest-level heading, which is displayed with the smallest size.

The heading under the H6 tags will be displayed with the lowest size.