To create a printable grid sheet, use a spreadsheet application like Excel and square the cells (each row should be the same length and height as each column). It does not matter what scale the grid paper is as long as all cells are square and the same size.
In Excel, the easiest way to do this is to first highlight the first 24 columns (to column X) and then change the cell width to 26 pixels. Next, select the first 40 rows and change the cell height to 26 pixels. Add borders around the cells that were resized. The worksheet is now a printable grid paper. The print area of the sheet may also need to adjusted to ensure only the formatted cells are printed.
Pre-made printable grid sheets are also available online through websites such as Printable Paper. Spending time finding an existing grid sheet online may be quicker than creating one from scratch on Excel. Pre-made sheets also come in a variety of different scales, such as 1 inch per square or 1/2 inch per square. The scale of the grid sheet may be important to certain projects or assignments when accurate measurements are needed rather than just reference points.