Bacterial Growth Calculator
📊 Growth Results
Final Population
—
Generations (n)
—
number of doublings
Growth Rate (µ)
—
per hour
Fold Increase
—
× initial population
Log₁₀ Increase
—
log cycles
Growth Timeline
| Time | Generations | Population | Log₁₀ |
|---|
How to Use the Bacterial Growth Calculator
Enter your initial bacterial population, the organism's doubling time, and the elapsed incubation time. You can also use the organism preset dropdown to auto-fill typical doubling times for common species.
- Initial Population (N₀): Starting cell count or CFU/mL at time zero.
- Doubling Time (g): Time required for the population to double. Can be in minutes or hours.
- Elapsed Time (t): Total incubation time in the same unit as doubling time.
Bacterial Growth Formula
Bacterial growth follows exponential kinetics during the log phase. The key equations are:
N(t) = N₀ × 2ⁿ
n = t / g
µ = ln(2) / g = 0.693 / g
Where:
N(t) = population at time t
N₀ = initial population
n = number of generations
g = doubling time
µ = specific growth rate
n = t / g
µ = ln(2) / g = 0.693 / g
Where:
N(t) = population at time t
N₀ = initial population
n = number of generations
g = doubling time
µ = specific growth rate
This calculator assumes ideal exponential phase growth with no nutrient limitation. Real cultures include lag phase, exponential phase, stationary phase, and death phase.
Common Bacterial Doubling Times
Doubling times vary greatly between species and growth conditions:
- E. coli: ~20 minutes at 37°C in rich media (LB broth)
- Salmonella typhimurium: ~30 minutes
- Staphylococcus aureus: ~60–90 minutes
- Bacillus subtilis: ~30 minutes
- Mycobacterium tuberculosis: ~12–24 hours
- Mycobacterium leprae: ~14 days (slowest known)