The HTML Strong Importance Element (<strong>) indicates that its contents have strong importance, seriousness, or urgency. Browsers typically render the contents in bold type.

Content categories Flow content, phrasing content, palpable content.
Permitted content Phrasing content.
Tag omission None, must have both a start tag and an end tag.
Permitted parents Any element that accepts phrasing content, or any element that accepts flow content.
Permitted ARIA roles Any
DOM interface HTMLElement

Attributes

This element only includes the global attributes.

Usage notes

The <strong> element is for content that is of "strong importance," including things of great seriousness or urgency (such as warnings). This could be a sentence that is of great importance to the whole page, or you could merely try to point out that some words are of greater importance compared to nearby content.

Typically this element is rendered by default using a bold font weight. However, it should not be used simply to apply bold styling; use the CSS font-weight property for that purpose. Use the <b> element to draw attention to certain text without indicating a higher level of importance. Use the <em> element to mark text that has stress emphasis.

Another accepted use for <strong> is to denote the labels of paragraphs which represent notes or warnings within the text of a page.

<b> vs. <strong>

It is often confusing to new developers why there are so many ways to express the same thing on a rendered website. <b> and <strong> are perhaps one of the most common sources of confusion, causing developers to ask "Should I use <b> or <strong>? Don't they both do the same thing?"

Not exactly. The <strong> element is for content that is of greater importance, while the <b> element is used to draw attention to text without indicating that it's more important.

It may help to realize that both are valid and semantic elements in HTML5 and that it's a coincidence that they both have the same default styling (boldface) in most browsers (although some older browsers actually underline <strong>). Each element is meant to be used in certain types of scenarios, and if you want to bold text simply for decoration, you should instead actually use the CSS font-weight property.

The intended meaning or purpose of the enclosed text should be what determines which element you use. Communicating meaning is what semantics are all about.

<em> vs. <strong>

Adding to the confusion is the fact that while HTML 4 defined <strong> as simply indicating a stronger emphasis, HTML 5 defines <strong> as representing "strong importance for its contents." This is an important distinction to make.

While <em> is used to change the meaning of a sentence as spoken emphasis does ("I love carrots" vs. "I love carrots"), <strong> is used to give portions of a sentence added importance (e.g., "Warning! This is very dangerous.") Both <strong> and <em> can be nested to increase the relative degree of importance or stress emphasis, respectively.

Examples

Basic example

<p>Before proceeding, <strong>make sure you put on your safety goggles</strong>.</p>

The resulting output:

Labeling warnings

<p><strong>Important:</strong> Before proceeding, make sure you add plenty of butter.</p>

This results in:

Specifications

Specification Status Comment
HTML Living Standard
The definition of '<strong>' in that specification.
Living Standard  
HTML5
The definition of '<strong>' in that specification.
Recommendation  
HTML 4.01 Specification
The definition of '<strong>' in that specification.
Recommendation  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 1Edge Full support YesFirefox Full support 1
Notes
Full support 1
Notes
Notes Before Firefox 4, creating a <strong> element incorrectly resulted in an HTMLSpanElement object, instead of the expected HTMLElement.
IE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yes

Legend

Full support  
Full support
See implementation notes.
See implementation notes.

See also