Width in pixels is absolute. For example, a table is 400 pixels wide regardless of the size of the browser window or monitor. Cell Padding and Cell Spacing refers to the margin inside the cell and the separation between cells of a table. Cell Spacing specifies how thick the grid lines of the table cells will be. This kind of table can be used very effectively for page layout.
Different monitors have different pixel maximums.
An older monitor may not be able to display more than 640 pixels horizontally and 480 pixels vertically. Some of this space will be used up by the browser itself. Tables should not be more than 550 pixels wide as a general rule. Add your content. When you are finished setting up your table, fill the cells with content by clicking on a cell and typing or pasting text or images.