It is normal to have a period of 3-4 days. The normal female menstrual cycle is around 28-30 days, with a period of 3-7 days and a volume of around 80mL, but individual differences vary and these factors are correlated with environmental changes, genetic factors, medication use, etc. There may be slight variations in both the period and the volume of menstruation, as well as in the various factors of the cycle. So for normal women 3-4 days of periods is normal, and the volume of periods as well as the cycle should be observed to determine if the periods are normal.