You cannot. The symptoms of COVID-19 overlap substantially with influenza (‘flu’) and other respiratory viral illnesses (like common colds).
So there is no way to distinguish among them without testing.
They are similar. Influenza (flu), the common cold, and COVID-19, are all contagious respiratory viral illnesses – but caused by different viruses.
Flu is caused by influenza viruses only. Whereas the common cold can be caused by a number of different viruses, including rhinoviruses, parainfluenza, and seasonal coronaviruses. The latter should not be confused with SARS-CoV-2, the virus that causes COVID-19.
Because all three have similar symptoms, it can be difficult to distinguish them based on symptoms alone. In general, flu is worse than the common cold, and symptoms are typically more intense and begin more abruptly.
We have described how you can tell if you have COVID, a cold or the flu. The short answer is no, sorry.