SEO Bold, Italic, and Underline

There is much debate concerning the significance of the Bold <b>, Strong <strong>, Italic <i>, and Underline <u> tags. In general these tags have little to no effect on page ranking and should be used sparingly to highlight words of importance such as terms, titles, or quoted text.  Repeatedly marking all keyword with the bold tag has very little effect on ranking. It is much better to use keywords in heading tags.

Excessive use of any of these tags makes the text difficult to read, because the reader has to figure out why the words are important, and if there are many occurrences their visual significance is diminished.

Compounding styles

Each one of these tags gives the content greater visual significance. They should only be compounded when necessary.  

This is a poor use of compounded style because one of the tags is sufficient. This sentence is better just using bold. It still has the same impact.

In this case we can use a compounded style because Greg said "Sometimes compounded style are good to use." It is useful here because the Italic tag indicates that the text is quoted and the Bold tag stresses the intonation of the quoted text.

Bold <b> or Strong <strong>

Both of these render the text in a similar visual appearance. Using Bold <b> is the traditional method defined in the HTML specification. Strong <strong> is the replacement for Bold <b> and is used in XHTML specification.  XHTML Transitional allows the use of both but it is recommended to use Strong <strong> instead of Bold <b>. XHTML Strict does not allow the use of the Bold <b> tag and causes the page to fail validation will normally results with a negative affect on Search Engine Ranking.

Underline tag not in XHTML Strict

It is also important to note that the Underline <u> tag has been deprecated from XHTML Strict and should therefor not be used as it will cause the page to fail validation and negatively influence Search Engine Ranking. An Underline can still be applied using Text Decoration style tag <span style="text-decoration: underline"> but it is better not to use it at all. Most current online editors still use the <u> tag and should not be used. 

Underling Hyperlinks

By default Hyperlinks that use the <a> tag have the text-decoration style applied. Some designers prefer to remove the underline and use color or italics to differentiate links from normal text. If this is the case then you should not apply inline style to make the link underlined.  A consistent visual style for links is very important for a reader to quickly identify what can be clicked. Adding inline style overrides on links typically confuses the reader.


Please update

Hi Clare,
Please update with how you rankings went after using bold and italic. I was told by a "Guru" that you should use bold and Italic in all content. SO far I havent been able to do any tests but I would be interested to know how you got on with your test.

paul wrote 5 years 48 weeks ago


I have never used these highlighting methods in any of my websites but I was helping one of my clients the other day and I noticed that his websites were doing well on google search although he had very little backlinks. I assumed that underlining and boldening of his keywords was doing the magic. Today I was also trying to do the same on one of my websites that isn't doing very well but I will wait and see what happens in a few days time

Mak wrote 6 years 18 weeks ago

bold, underline & italic

I had a steady page 1 position 2 ranking for one keyword phrase and a page 2 position 2 ranking for another keyword phrase (different product pages)
I had read about highlighting keywords and followed a suggestion that the phrase for which I was ranking should be highlighted strong, italic and underlined.
I did this and when Google next crawled the site, my page 1 position 2 slipped to page 3 and my page 2 position 2 slipped out of this world to page 300 odd.
No other linking or SEO work was done to these pages.
As a test I have now highlighted a different keyphrase on a page I am ranking on page 1 for to see if this also suffers a drop and I have removed the highlighting altogether on the other pages to see if they return to their high positions when next crawled. I’d be interested to hear your thoughts on this

Claire wrote 6 years 27 weeks ago
gbrandys's picture

Possibly due to overuse

Hi Claire,
I suspect that your drop in ranking may be due to many people overusing the bold tag specifically to bump their page ranking. Google's ranking algorithms are always changing and never published. It could be the case that at one point Google did give extra value to keywords if they were bold. Since then they may have noticed that people are exploiting it and reduce rank or blacklist pages that use it.
The are few SEO rules that stand the test of time. The two long term rules we follow are:

  1. SEO should always enhance the reader's experience and not make content harder to read or navigate.
  2. Never use gimick or 'blackhat' methods as they will always eventually backfire.
gbrandys wrote 6 years 27 weeks ago

Add your comment

The content of this field is kept private and will not be shown publicly. If you have a Gravatar account associated with the e-mail address you provide, it will be used to display your avatar.
     d9@HH   E5SS@58HE    .dM5M8b.       d9@HH    dS9@   
d@PH98 9H@ dE9P YE9b d@PH98 d8E9H
dMP @ES S9E YM8b. dSHP dMP @ES @9S
d5P S@@ @MM8H@Hb. "Y@SH9@" d5P S@@ HEE
dME 5E5 "Y@9b .dSP""YSb. dME 5E5 58E
5E58M@E88@ MEE H9M 595 5E58M@E88@ M@5
58M YHMb dHSP Y5Hb d5EP 58M @@H
99H "YE959P" "Y555HP" 99H M5E58S@