When does a cold become contagious?

According to MedlinePlus, a cold is most contagious within the first three days of symptoms, and typically is no longer contagious after the first week of illness. Colds are transferable from person-to-person through direct and indirect contact.

Droplets produced from sneezing and coughing, as well as touching an infected object or surface and then the eyes, nose or mouth, are the most common ways to transfer a cold, explains MedlinePlus. Symptoms of a cold typically present within a few days of contact with the person or virus but can take as long as a week. Cold symptoms last for about one week.