Use this handy guide as a reference when writing HTML or xHTML. I list all the HTML tags you’ll ever need – and all the ones you shouldn’t use too! For each tag, I explain its proper use when writing Semantic HTML. I hope you find it useful.

I haven’t listed absolutely every HTML tag ever, as some of them are too obscure to be worth mentioning.

Tag What it is When to use it
<a> Anchor (most commonly a link) Vital. Use to create links in content. Use the title attribute whenever the contents of the <a>…</a> pair do not accurately describe what you’ll get from selecting the link. Title attribute often displays as a tooltip in visual browsers, which may be a helpful usability aid.
<abbr> Defines an abbreviation Works in a similar way to <dfn> and <acronym>, using a title attribute (displays a tooltip in standard visual browsers). e.g. <abbr title=”Hypertext markup language”>HTML</abbr>
<ACRONYM> Defines an acronym Works in a similar way to <abbr> and <dfn>, using a title attribute (displays a tooltip in standard visual browsers).
<ADDRESS> Used for marking up a physical (e.g. mailing) address Not commonly used. Recommend looking into microformats, which allow for more detail and interoperability.
<APPLET> Inserts a Java applet The old way to insert a Java app. Use <object> instead today.
<AREA> Hotspot in image map Avoid image maps where possible. Occasionally necessary.
<BASE> Specifies the base location of the document. Use only when necessary. Adjusts any relative links and paths within the document.
<BASEFONT> Sets default font size Display info – never use it
<BIG> Larger text Display info – never use it
<BLINK> Makes text blink You go to hell if you use this
<BLOCKQUOTE> Large quoted block of text Use for any quoted text that constitutes one or more paragraphs (note: should contain <p> tags as well). Use <q> for quotations within a paragraph. Often used in conjunction with <cite> to cite the quotation’s source.
<BODY> Document body Essential (unless you’re using frames)
<BR> Line break This is arguably display information. Still in common use, but use with restraint.
<B> Bold text Display info – never use it
<BUTTON> Used for a standard clickable button within a form Often better than <input type=”button” /> or <input type=”submit” />, as it allows you to assign different styles based on the HTML element alone, whereas differentiating style based on the type of input is less well supported.
<CAPTION> Caption for a table: describes the table’s contents The correct way to assign a title to a table
<CENTER> Centred block Display info – never use it. Use <div> or some other block-level tag with the style text-align:center instead
<CITE> Defines a citation Defines the source of a quotation (in conjunction with content in <q> or<blockquote> pairs).
<CODE> Defines an extract of code Not commonly used. Similar to <pre> tag, but collapses consecutive white spaces and line breaks in the source.
<COL> Identifies a particular column in a table Can be very useful. e.g. <col class=”namecol”> can be applied to each first column in a series of tables, then the width of each column may be set to be equal in the stylesheet, overriding the table’s natural tendency to adjust its own column widths to fit its contents.
<DFN> Definition of a term Works in a similar way to <abbr> and <acronym>, using a title attribute (displays a tooltip in standard visual browsers).
<DIR> Directory list Now deprecated. Use a standard <ul> or other list instead.
<DIV> Division Specifies a logical division within a document. Use it to separate or identify chunks of content that are not otherwise distinguished naturally using other tags.
One of the most common HTML tags.
<DL> Definition list Contains one or more definition-term / definition-description pairs.
<DT> Definition term Used as part of a <dt></dt><dd></dd> pair within a definition list (<dl></dl>)
<DD> Definition description
<EM> Emphasis Commonly used in place of the old <i> (italics) tag to indicate emphasis (but less than <strong>)
<FONT> Font settings Display info – never use it
<FORM> Input form Essential for data input
<H1> Level 1 header Aim to have one H1 on each page, containing a description of what the page is about.
<H2> Level 2 header Defines a section of the page
<H3> Level 3 header Defines a sub-section of the page (should always follow an H2 in the logical hierarchy)
<H4> Level 4 header Etc. Less commonly used
<H5> Level 5 header Less commonly used. Only complex academic documents will break down to this level of detail.
<H6> Level 6 header Less commonly used
<HEAD> Document head Essential. Contains information about a page that does not constitute content to be communicated as part of the page.
<HR> Horizontal rule Display info with no semantic value – never use it. “Horizontal”, by definition, is a visual attribute.
<HTML>   Core element of every web page.
<IMG > Show an image Vital. Always use the alt or longdesc attributes when the image has content value
<INPUT> Input fields within forms Vital. (I prefer to use <button> for buttons and submit buttons though)
<ISINDEX> Old type of search input Not really used any more. Use <form> instead.
<I> Italicised text Display info – never use it
<KBD> Keyboard input Display info – never use it
<LINK> Defines a relationship to another document Commonly used to reference external stylesheets, but has other minor uses
<LI> List item Specifies an item in an unordered or ordered list (<ul> or <ol>)
<MAP> Client-side imagemap May have occasional value, but only use when absolutely necessary
<MARQUEE> Makes text scroll across the screen See <blink>
<MENU> Menu item list Deprecated. Do not use. Use other standard list types instead.
<META> Meta-information Useful way to insert relevant information into the <head> section of the page that does not need to be displayed.
<OL> Ordered list Type of list where the order of elements has some meaning. Generally rendered with item numbers (best managed with CSS).
<OPTION> Selection list option Vital for options within a drop-down control.
<PARAM> Parameter for Java applet Used in conjunction with an <object> or <applet> tag to pass additional setting information at runtime.
<PRE> Preformatted text Renders text in a pre-formatted style, preserving line breaks and all spaces present in the source. May be useful. (This one’s a paradox, as it is strictly display info that applies only to visual browsing, but it’s still so commonly used and useful that I’m hesitant to advise against using it.)
<P> Paragraph Only use to denote a paragraph of text. Never use for spacing alone.
<Q> Short quotation Use for inline quotations (whereas <blockquote> should be used for quotations of a paragraph or more). Often used in conjunction with <cite>to cite the quotation’s source.
<SAMP> Denotes sample output text Similar to the <code> tag. Rarely used. Avoid.
<SCRIPT> Inline script (e.g. JavaScript) It’s better to have all scripts as separate files than to write inline or in the<head> section, however still has its uses.
<SELECT> Selection list A drop-down selector for a form.
<SMALL> Smaller text Display info – never use it
<SPAN> An inline span within text Use to apply meaning (and style) to a span of text that goes with the flow of content (whereas a <div> tag is block-level and breaks the flow)
<Strikeout>   Display info – never use it
<STRONG> Strong emphasis Use this instead of the old <b> tag.
<STYLE> CSS style settings Normally used in <head> section of a page. Try to use external stylesheets, to enable you to apply different styles for different output media.
<SUB> Subscript text Arguably display info – recommend using alternative tags (e.g. <cite>). May be required in some academic uses, e.g. Chemical formulas.
<SUP> Superscript text
<TABLE> Table Use for repeated data that has a naturally tabular form. Never use for layout purposes.
<TD> Table data cell A cell containing actual data. If a cell actually contains a descriptor or identifier for a row or column, use a <th> (table header) tag, not a <td>.This usually applies to column headers (within a <thead>), column footers (within a <tfoot>), as well as row headers (usually the first cell in a row in the <tbody>).
<TEXTAREA> Multi-line text input area in a form Essential
<TH> Table column or row header cell May appear in a <thead> (to denote a column header cell), <tbody> (to denote a row header), and in <tfoot> (to denote a column foot cell, e.g. a total)
<TBODY> Indicates the main body of a data table It is always worth using this tag, as well as using <thead> and <tfoot>where appropriate.
Note that it is permissible to have more than one <tbody><thead>, and<tfoot> in the same table.
<THEAD> The head section of a table The place to put column header cells (<th>)
<TFOOT> The foot section of a table Good place to put e.g. summary data, such as totals. Note that it goes before the <tbody> tag!
<TITLE> Document title Essential
<TR> Table row Essential with tables
<TT> “Teletype” – simulates typewriter output Similar to <pre>, except that it collapses white space like normal HTML (whereas <pre> leaves all consecutive white space intact). Avoid if possible
<UL> Unordered list Essential. Use for lists where the order or items has no particular importance.
<U> Underline text Display info – never use it
<VAR> Variable in computer code Obscure tag, may only be useful in academic documents. Avoid.
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