What is HTML?

An HTML table is a table element containing thead and tbody, with th cells for headers and td cells for data.

Who uses it

Web pages, email templates and anything pasted into a CMS.

Reading HTML

The first table in the markup is used. Cell contents are stripped of inline tags and entities are decoded, so <td><b>Total</b> </td> arrives as Total. Nested tables inside a cell are not descended into.

Writing HTML

Semantic markup: a real thead, a real tbody, th for the header row. Angle brackets and ampersands in your data are escaped, so a value like <script> is written safely and shows as text on the page.

What it can hold

HTML is a markup language. The only common table format with real header cells, spans and nested tables. A machine can read the table back out of it without guessing, which is what makes it safe to convert into and out of.

It keeps

Nested values. A cell can hold a list or an object rather than only a single value.
A line break inside a cell, which survives rather than ending the row.
Presentation - weight, alignment, colour and widths - alongside the values themselves.
A header that is marked as one, rather than being the first row by convention.

It cannot express

Types. Every value is text. A column of digits is indistinguishable from a column of numbers until something downstream decides to read it as one, which is where a leading zero usually disappears.
A null. An absent value and an empty one look the same, and nothing in the file says which was meant.
A partial read. The document has to be complete to mean anything, so a truncated file yields nothing and a large one has to be held in memory whole.

What it looks like

Example HTML

<table>
  <thead>
    <tr><th>id</th><th>name</th><th>role</th><th>started</th><th>hours</th></tr>
  </thead>
  <tbody>
    <tr><td>007</td><td>Halima Yusuf</td><td>Analyst, data</td><td>2024-03-15</td><td>38.5</td></tr>
    <tr><td>012</td><td>Jonah "Jo" Pryce</td><td>Engineer</td><td>2025-11-02</td><td></td></tr>
    <tr><td>104</td><td>Wei Chen</td><td>Manager</td><td>2023-06-30</td><td>40</td></tr>
  </tbody>
</table>

Questions

How do I open HTML files?

Any text editor will show you the contents. To read it as a table, paste it into the converter on this site and it appears in an editable grid. Nothing is uploaded.

Is HTML a good format for sharing data?

It depends who is receiving it. Web pages, email templates and anything pasted into a CMS. If the recipient is outside that group, a plain CSV travels further than anything else.