<Dd> g r = ln ⁡ (N (t) / N (0)) t (\ displaystyle gr = (\ frac (\ ln \ left (N (t) / N (0) \ right)) (t))) </Dd> <Ul> <Li> N (t) (\ displaystyle N (t)) = the number of cells at time t </Li> <Li> N (0) (\ displaystyle N (0)) = the number of cells at time 0 </Li> <Li> g r (\ displaystyle gr) = growth rate </Li> <Li> t (\ displaystyle t) = time (usually in hours) </Li> </Ul> <Li> N (t) (\ displaystyle N (t)) = the number of cells at time t </Li> <Li> N (0) (\ displaystyle N (0)) = the number of cells at time 0 </Li>

If the growth rate of a population increases the doubling time