Tablizer

Convert HTML to RDF Online

Paste a HTML table below, edit it if you need to, and get RDF back. The conversion runs in your browser, so nothing is uploaded, there is no size limit and there is no signup.

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The only part of this site that uses a server. The address is sent to it so the page can be fetched, because a browser is not allowed to fetch someone else's page itself. Your own files are never involved.

Nothing here is uploaded. The parsing happens on this page.
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The output will appear here once there is a table to convert.

What HTML is

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

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

What RDF is

RDF in Turtle syntax: subject, predicate, object triples describing each row.

Linked data and semantic web projects.

What changes when you convert HTML to RDF

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

Each row becomes a subject with one predicate per column, under an example.org namespace you will want to change.

What carries over from HTML to RDF

HTML records 2 things about a table that RDF has no way to hold.

RDF wants a type for each column, and HTML does not record one, so each column is typed from what its values look like. A column of digits that should stay text - a zip code, a phone number, a leading-zero id - is the usual thing to check afterwards.

RDF has no header row. The column names are repeated as keys on every record instead, which is why the result is bigger on disk than the table it came from.

Anything visual in the HTML - weight, alignment, colour, column widths - has no counterpart in RDF and is dropped. The values are what survives.

The result can be read a record at a time, and appended to by adding to the end of it. That is worth having for a table too large to hold in memory, and it means a RDF file that is cut off part way through still gives you every record before the cut.

The identifier 007 comes out of the RDF as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.

The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a RDF file goes wrong.

The quotes around Jonah "Jo" Pryce are escaped with a backslash in the RDF.

A worked example

Three rows of staff data, with an identifier that has a leading zero, a value containing a comma, a value containing quotes and one blank cell. Those are the four places formats disagree, so they are the four places to look.

HTML in
<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>
RDF out
@prefix ex: <http://example.org/> .

ex:row1
    ex:id "007" ;
    ex:name "Halima Yusuf" ;
    ex:role "Analyst, data" ;
    ex:started "2024-03-15" ;
    ex:hours "38.5" .

ex:row2
    ex:id "012" ;
    ex:name "Jonah \"Jo\" Pryce" ;
    ex:role "Engineer" ;
    ex:started "2025-11-02" ;
    ex:hours "" .

ex:row3
    ex:id "104" ;
    ex:name "Wei Chen" ;
    ex:role "Manager" ;
    ex:started "2023-06-30" ;
    ex:hours "40" .

Questions

How do I convert HTML to RDF?

Paste your HTML into the box above or drop the file onto it. Check the table in the grid, then copy or download the RDF from the output panel. It takes one step and the data never leaves your browser.

Is there a limit on file size?

No. The work happens on your own machine, so the limit is your machine's memory rather than an upload cap. A file with tens of thousands of rows converts in a second or two.

Is my data uploaded anywhere?

No. The parsing and generating are done by JavaScript running on this page. You can watch the network tab while you convert and see that nothing is sent.

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