The common cold is contagious starting about 1 to 2 days before symptoms appear and remains contagious as long as symptoms are present, typically about 7 to 10 days. In some cases, especially with young children, people with weakened immune systems, or those with respiratory conditions, the contagious period can last up to two weeks or longer

. You are most contagious during the first 3 to 4 days after symptoms begin, when symptoms like coughing and sneezing are at their worst. After this period, the likelihood of spreading the virus decreases but you can still be contagious until symptoms fully resolve

. In summary:

• Contagious period starts 1-2 days before symptoms.
• Most contagious during first 3-4 days of symptoms.
• Usually contagious for about 7 to 10 days total.
• Can be contagious up to 2 weeks in some cases, especially in children or those with weakened immunity