g = t × ln(2) / ln(N₂/N₁)
Generation time (g) is the time for a bacterial population to double during the log phase. g = t/n, where n = number of generations = log₂(N₂/N₁) = 3.322 × log₁₀(N₂/N₁). Typical generation times: E. coli 20 min, S. aureus 30 min, M. tuberculosis 15-20 hours, Treponema pallidum 33 hours. Generation time is measured during exponential (log) phase only — lag and stationary phases don't follow this equation. Factors affecting g: temperature (optimum varies by species), nutrients, pH, oxygen availability. Generation time is important for predicting food spoilage rates, infection progression, and industrial fermentation productivity.