Estimate bacterial doubling time from two concentration measurements and the time between them. It also shows the implied growth rate, number of generations, and percentage increase, helping you compare culture runs when both measurements use the same method and the culture remained in a comparable growth phase.
A shorter doubling time indicates faster exponential growth under the measured conditions. The result is only meaningful when the ending concentration exceeds the starting concentration.
Two-point estimates can be distorted by lag phase, stationary phase, sampling error, or measurements made with different calibration methods.
A culture rising from 1,000,000 to 8,000,000 cells/mL in 4.5 hours completes 3 generations, giving a doubling time of 1.5 hours.
No. This exponential doubling-time calculation requires an ending concentration greater than the starting concentration. A decrease should be analyzed as decay or loss.
A change in assay, calibration, dilution correction, or reporting unit can look like biological growth and distort the calculated rate.
No. It summarizes the change between two points and assumes an exponential path; additional time points are needed to evaluate that assumption.
Yes, if the elapsed-time unit is treated consistently. The result will be in the same time unit entered even though the interface labels the default unit as hours.
The logarithmic growth rate is zero, so a finite doubling time cannot be calculated.
| Field | Meaning |
|---|---|
| Growth \1Ate | Calculated output |
| Generations | Calculated output |
| Increase | Calculated output |