average size for table runners
Basic Dimensions. A typical table runner hangs down about 10 to 15 inches or so on each side of the table, no matter the shape of the table. When measuring for a table runner, add 20 to 30 inches to the length of the table to get the length of the runner. The width offers more variation, ranging from 1/3 to 1/4 the width of the table. Use the thinner width on a smaller table, especially if the table is round.
Working With Width. A standard table runner measures between 14 and 17 inches wide, but table runners easily can be customized to best fit your particular table. Measure the width of your table and choose a runner close to 1/3 the width. When making your own runner, add between 1 and 1 1/2 inches to the measurement for seam allowance when cutting fabric.