# Headings

HTML provides not only plain paragraph tags, but six separate header tags to indicate headings of various sizes and thicknesses. Enumerated as heading 1 through heading 6, heading 1 has the largest and thickest text while heading 6 is the smallest and thinnest, down to the paragraph level. This topic details proper usage of these tags.

# Using Headings

Headings can be used to describe the topic they precede and they are defined with the <h1> to <h6> tags. Headings support all the global attributes.

  • <h1> defines the most important heading.
  • <h6> defines the least important heading.

Defining a heading:

<h1>Heading 1</h1>
<h2>Heading 2</h2>
<h3>Heading 3</h3>
<h4>Heading 4</h4>
<h5>Heading 5</h5>
<h6>Heading 6</h6>

# Correct structure matters

Search engines and other user agents usually index page content based on heading elements, for example to create a table of contents, so using the correct structure for headings is important.

In general, an article should have one h1 element for the main title followed by h2 subtitles – going down a layer if necessary. If there are h1 elements on a higher level they shoudn't be used to describe any lower level content.

Example document (extra intendation to illustrate hierarchy):

<h1>Main title</h1>
<p>Introduction</p>

    <h2>Reasons</h2>

        <h3>Reason 1</h3>
        <p>Paragraph</p>

        <h3>Reason 2</h3>
        <p>Paragraph</p>

    <h2>In conclusion</h2>
    <p>Paragraph</p>

# Syntax

  • <h1>...</h1>
  • <h2>...</h2>
  • <h3>...</h3>
  • <h4>...</h4>
  • <h5>...</h5>
  • <h6>...</h6>

# Remarks

  • An `h1`–`h6` element must have both a start tag and an end tag.[**1**](https://www.w3.org/TR/html-markup/h1.html)
  • `h1`–`h6` elements are block level elements by default (CSS style: `display: block`).[**2**](https://www.w3.org/TR/html401/struct/global.html#h-7.5.3)
  • `h1`–`h6` elements should not be confused with the [section element](http://stackoverflow.com/documentation/html/311/sectioning-elements#t=201607262130086028708)
  • Heading tags (`h1`–`h6`) are not related to the `head` tag.
  • Permitted Content: [phrasing content](https://www.w3.org/TR/html-markup/terminology.html#phrasing-content)
  • The different CSS-styles for headings differ usually in `font-size` and `margin`. The following CSS-settings for `h1`–`h6` elements can serve as an orientation (characterized as 'informative' by the [W3C](https://www.w3.org/TR/CSS21/sample.html))
  • Search engine spiders (the code that adds a page to a search engine) automatically pays more attention to higher importance (h1 has most, h2 has less, h3 has even less, ...) headings to discern what a page is about.