HTML Guides for row

In HTML, the structure of a <table> is implicitly defined by its rows and columns. The first <tr> in a table (or table section like <thead>, <tbody>, or <tfoot>) establishes the expected column count for the entire table. When a subsequent row contains more cells than the first row, the validator raises this error because the table’s column grid becomes inconsistent.

Browsers will still attempt to render mismatched tables, but the results can be unpredictable and problematic. Screen readers and other assistive technologies rely on a well-formed table grid to correctly associate data cells with their headers. An inconsistent column count can cause these tools to misread or skip content, making the table inaccessible to users who depend on them. Additionally, inconsistent tables are harder to style with CSS and can lead to unexpected layout shifts.

There are several common causes for this issue:

• Missing cells in the first row — The first row has fewer <td> or <th> elements than subsequent rows.
• Forgotten colspan — A cell in the first row should span multiple columns but is missing a colspan attribute.
• Extra cells in later rows — A row further down the table has more cells than intended.
• Mismatched colspan arithmetic — The sum of cells and their colspan values doesn’t add up consistently across rows.

To fix this, review every row in the table and ensure the total column count (accounting for colspan and rowspan attributes) is the same for each row.

Examples

Incorrect: second row has more columns than the first

The first row defines 1 column, but the second row has 2 columns.

<table>
  <tr>
    <td>Liza</td>
  </tr>
  <tr>
    <td>Jimmy</td>
    <td>14</td>
  </tr>
</table>

Fixed: add missing cells to the first row

Make both rows have 2 columns by adding a header or data cell to the first row.

<table>
  <tr>
    <th>Name</th>
    <th>Age</th>
  </tr>
  <tr>
    <td>Jimmy</td>
    <td>14</td>
  </tr>
</table>

Fixed: use colspan if the first row intentionally spans the full width

If the first row is meant to be a single spanning header, use colspan to match the total column count.

<table>
  <tr>
    <th colspan="2">Student Info</th>
  </tr>
  <tr>
    <td>Jimmy</td>
    <td>14</td>
  </tr>
</table>

Incorrect: later row exceeds column count with extra cells

<table>
  <tr>
    <th>Name</th>
    <th>Age</th>
  </tr>
  <tr>
    <td>Liza</td>
    <td>12</td>
    <td>Extra cell</td>
  </tr>
</table>

Fixed: remove the extra cell or expand the header row

<table>
  <tr>
    <th>Name</th>
    <th>Age</th>
    <th>Notes</th>
  </tr>
  <tr>
    <td>Liza</td>
    <td>12</td>
    <td>Extra cell</td>
  </tr>
</table>

Incorrect: colspan mismatch causes inconsistent totals

The first row spans 3 columns total (1 + colspan="2"), but the second row has 4 cells.

<table>
  <tr>
    <th>Name</th>
    <th colspan="2">Contact</th>
  </tr>
  <tr>
    <td>Liza</td>
    <td>liza@example.com</td>
    <td>555-0100</td>
    <td>Room 4</td>
  </tr>
</table>

Fixed: adjust colspan or cell count so all rows match

<table>
  <tr>
    <th>Name</th>
    <th colspan="3">Contact &amp; Location</th>
  </tr>
  <tr>
    <td>Liza</td>
    <td>liza@example.com</td>
    <td>555-0100</td>
    <td>Room 4</td>
  </tr>
</table>

When debugging this issue, count the effective columns for each row by adding up the number of cells plus any additional columns contributed by colspan values (a colspan="3" cell counts as 3 columns). Every row in the table must produce the same total.

The HTML specification requires that every row in a table has at least one cell that starts on that row. A “cell beginning on a row” means a <td> or <th> element that is directly placed in that <tr>, as opposed to a cell that merely spans into it via rowspan from an earlier row. When the validator encounters a row with no cells beginning on it, it flags the error because the row is structurally meaningless — it contributes nothing to the table’s data model.

This issue commonly arises in two scenarios:

1. Empty <tr> elements — A <tr> that contains no <td> or <th> children at all. This sometimes appears when developers use empty rows for visual spacing, or when content management systems generate leftover markup.
2. Rows fully covered by rowspan — When cells in preceding rows use rowspan values large enough to span over an entire subsequent row, that subsequent row ends up with no cells beginning on it, even if it technically “has” cells passing through it.

This matters for several reasons. Screen readers and other assistive technologies rely on a well-formed table structure to navigate cells and announce their content. An empty or fully-spanned row confuses this navigation. Browsers may also handle malformed tables inconsistently, leading to unexpected rendering. Ensuring every row has at least one cell that begins on it keeps your tables semantically correct and accessible.

How to fix it

• Remove empty rows. If a <tr> has no cells and serves no purpose, delete it entirely.
• Add cells to the row. If the row is intentional, populate it with <td> or <th> elements (they can be empty if needed).
• Adjust rowspan values. If previous cells span too many rows, reduce their rowspan so that every row still has at least one cell of its own.
• Use CSS for spacing. If empty rows were used for visual spacing, use CSS margin, padding, or border-spacing instead.

Note that self-closing <tr /> elements are treated the same as <tr></tr> — they produce an empty row and will trigger this error.

Examples

Empty row in <tbody> (incorrect)

<table>
  <tbody>
    <tr>
    </tr>
    <tr>
      <td>Data</td>
    </tr>
  </tbody>
</table>

The first <tr> has no cells, so the validator reports that row 1 of the <tbody> row group has no cells beginning on it.

Empty row removed (correct)

<table>
  <tbody>
    <tr>
      <td>Data</td>
    </tr>
  </tbody>
</table>

Row fully covered by rowspan (incorrect)

<table>
  <tbody>
    <tr>
      <td rowspan="3">Spans three rows</td>
      <td rowspan="3">Also spans three</td>
    </tr>
    <tr>
    </tr>
    <tr>
    </tr>
  </tbody>
</table>

Rows 2 and 3 have no cells beginning on them — all cells originate from row 1. Even though cells pass through those rows via rowspan, the validator still requires at least one cell to begin on each row.

Corrected rowspan with cells on every row (correct)

<table>
  <tbody>
    <tr>
      <td rowspan="3">Spans three rows</td>
      <td>Row 1 detail</td>
    </tr>
    <tr>
      <td>Row 2 detail</td>
    </tr>
    <tr>
      <td>Row 3 detail</td>
    </tr>
  </tbody>
</table>

Each row now has at least one <td> that begins on it, satisfying the requirement.

Using CSS instead of empty rows for spacing (correct)

<table>
  <tbody>
    <tr>
      <td>First item</td>
    </tr>
    <tr style="height: 1.5em;">
      <td>Second item with extra space above</td>
    </tr>
  </tbody>
</table>

Instead of inserting an empty row for spacing, apply CSS to the row or cells that need additional space.