Bacterial Growth Calculator
Cell count after a period of exponential growth, the number of generations and the time to reach a million per millilitre.
Results
Final count
16,777,216,000
CFU/mL
Generations
24.000
Log of the count
10.2247
Growth rate
2.07944
1/h
Hours
3.322
h
What this tool does
Doubling every twenty minutes, a thousand cells become sixteen billion in eight hours — which is exactly why food left at room temperature stops being safe long before it looks or smells wrong. Real cultures only grow this way in the exponential phase; they start slowly and stop when nutrients run out or waste builds up.
Formula
N = N₀ × 2^(t ÷ g)
Variables
| Symbol | Meaning | Unit |
|---|---|---|
n0 | Initial count | CFU/mL |
gt | Generation time | min |
t | Time | h |
N | Final count | CFU/mL |
GN | Generations | — |
LG | Log of the count | — |
MU | Growth rate | 1/h |
TM | Hours | h |
Worked example
- Initial count1000 CFU/mL
- Generation time20 min
- Time8 h
- Final count16,777,216,000 CFU/mL
- Generations24.000
- Log of the count10.2247
- Growth rate2.07944 1/h
- Hours3.322 h
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
- This tool is informational only. It does not diagnose, treat or replace a qualified health professional. Speak to a doctor before making decisions about your health.