I find that the runner can also be a beautiful decorative element to enrich a table set with a tablecloth. The runners, positioned transversely, will serve in this case to embellish and emphasize each table setting by creating a sequence of interesting geometries, which will interrupt the monotony of a very long or perhaps a little unadorned tablecloth. I also really like to mix solid colors and patterns, or stripes and floral fabrics, linked by a common thread like color or in elegant chromatic contrast.
As for the measures, the ideal size of a runner, I can tell you that it is good to know that if the width must be that of a placé (table place), thus allowing us to place cutlery and napkins next to the plate, the length will be valid more or less the same rules valid for choosing the most correct size for your tablecloth,
That is, the runner must have a fall of about 30 cm on both sides. Our runners vary from 140 to 180 cm in length depending on whether they have edges to embellish them or not.
Another option can be to place only one runner longitudinally on the table, in which case you will need a longer runner and in all probability tailor-made to adapt to the measurements of your table, always considering 30/40 cm of fall side in addition to the length of the table itself. In these cases, generally, the runner is superimposed on a tablecloth, and place cards or placemats are added for each table place.