<!DOCTYPE HTML> <html> <head> <title>basis of percentage widths</title> <style type="text/css"> td { border: 3px inset blue; } </style> </head> <body> <!-- The difference between the border-box width of the table and the width allocated to the columns is: 2px = table border-left-width 9px = table padding-left 25px = 5 * table border-spacing-x 5px = table padding-right 2px = table border-left-width ================================= 43px --> <table cellpadding="3" cellspacing="5" border="2" style="padding: 3px 5px 7px 9px"> <tr> <td width="25%">x</td> <td width="38">x</td> <td><div style="width:38px">x</div></td> <td><div style="width:38px">x</div></td> </tr> </table> <table cellpadding="3" cellspacing="5" border="2" style="padding: 3px 5px 7px 9px" width="243"> <tr> <td width="25%">x</td> <td width="38">x</td> <td><div style="width:38px">x</div></td> <td><div style="width:38px">x</div></td> </tr> </table> <table cellpadding="3" cellspacing="5" border="2" style="padding: 3px 5px 7px 9px" width="443"> <tr> <td width="25%">x</td> <td width="38">x</td> <td><div style="width:38px">x</div></td> <td><div style="width:38px">x</div></td> </tr> </table> <table cellpadding="3" cellspacing="5" border="2" style="padding: 3px 5px 7px 9px" width="223"> <tr> <td width="25%">x</td> <td width="38">x</td> <td><div style="width:38px">x</div></td> <td><div style="width:38px">x</div></td> </tr> </table> </body> </html>