How to set up fixed width for ?

For Bootstrap 4.0:

In Bootstrap 4.0.0 you cannot use the col-* classes reliably (works in Firefox, but not in Chrome). You need to use OhadR’s answer:

<tr>
  <th style="width: 16.66%">Col 1</th>
  <th style="width: 25%">Col 2</th>
  <th style="width: 50%">Col 4</th>
  <th style="width:  8.33%">Col 5</th>
</tr>

For Bootstrap 3.0:

With twitter bootstrap 3 use: class="col-md-*" where * is a number of columns of width.

<tr class="something">
    <td class="col-md-2">A</td>
    <td class="col-md-3">B</td>
    <td class="col-md-6">C</td>
    <td class="col-md-1">D</td>
</tr>

For Bootstrap 2.0:

With twitter bootstrap 2 use: class="span*" where * is a number of columns of width.

<tr class="something">
    <td class="span2">A</td>
    <td class="span3">B</td>
    <td class="span6">C</td>
    <td class="span1">D</td>
</tr>

** If you have <th> elements set the width there and not on the <td> elements.