⏱ Population Doubling Time Calculator
Calculate the population doubling time (PDT) and growth rate of cultured cells using the initial cell count, final cell count, and culture duration.
Calculator
Formula
Population Doubling Time (PDT) = (t × log(2)) ÷ log(Nf / Ni)
Where:
- Ni = Initial cell number
- Nf = Final cell number
- t = Culture duration
Growth Rate = Population Doublings ÷ Culture Duration
Worked Example
A culture expands from 500,000 cells to 4,000,000 cells over 72 hours.
Fold Expansion = 4,000,000 ÷ 500,000 = 8
Population Doublings = log(8) ÷ log(2) = 3
Population Doubling Time = 72 ÷ 3 = 24 hours
- Population Doubling Time = 24.00 hours
- Growth Rate = 0.0417 doublings/hour
Laboratory Notes
- Use viable cell counts whenever possible.
- Measure culture duration accurately from seeding to harvesting.
- Maintain identical culture conditions throughout the experiment.
- Population doubling time is influenced by passage number, media composition, and cell health.
- Compare doubling times only between experiments performed under similar conditions.
References
- Freshney RI. Culture of Animal Cells: A Manual of Basic Technique and Specialized Applications.
- ATCC Animal Cell Culture Guide.
- Hayflick L. The Limited In Vitro Lifetime of Human Diploid Cell Strains. Experimental Cell Research (1965).
- Thermo Fisher Scientific Cell Culture Technical Resources.