You are contagious with a cold starting about one to two days before symptoms appear and remain contagious for up to seven days, with the highest contagiousness during the first three to four days of symptoms. In some cases, contagiousness can last up to two weeks, especially if symptoms like coughing persist. The contagious period begins during the incubation phase (1-3 days after exposure) and peaks when symptoms are most severe, such as runny nose, coughing, and sneezing. After symptoms improve, the risk of spreading the virus diminishes, but lingering cough or nasal symptoms may still pose some risk of transmission for a longer period.