The COVID-19 incubation period is estimated to be within 14 days of exposure, with most cases occurring around five days following exposure. 


The onset of fever and respiratory symptoms occurred in a family cluster of infections approximately three to six days after suspected exposure. Furthermore, in a study of 10 patients with documented COVID-19 pneumonia, the mean incubation period was estimated to be five days.


References- 

1. https://www.ncbi.nlm.nih.gov/pubmed?term=31986261

2. https://www.ncbi.nlm.nih.gov/pubmed?term=31995857