Use the GridView.CellPadding property to control the spacing between the contents of a cell and the cell's border. The padding amount specified is added to all four sides of the cell.

All cells in the same column of a System.Web.UI.WebControls.GridView control have the same width. The padding amount is applied to the widest cell and all other cells in the column have this cell width. Similarly, all cells in the same row have the same height. The padding amount is applied to the tallest cell in the row and all other cells in the row have this cell height. Individual cell sizes cannot be specified.