<!DOCTYPE HTML> <html> <head> <title>Percent widths on table cells</title> <style type="text/css"> table { border-spacing: 3px 5px; padding: 2px 3px 4px 5px; } td { border: none; padding: 0; } </style> </head> <body> <table><tr> <td style="background: yellow">xxxxx</td> <td style="background:aqua" width="100%">x</td> </tr></table> <table><tr> <td style="background:aqua" width="100%">x</td> <td style="background: yellow">xxxxx</td> </tr></table> </body> </html>