Cell Doubling — Doubling Time & Growth Rate

Cell Doubling Time

Calculate the growth kinetics during the exponential phase · T_d = ln(2) / μ

Input parameters

Time unit

Population unit

N₀

Initial Population

Initial population count (OD600)

0.001100

Nₜ

Final Population

Final population count (OD600)

0.0011000

t₀

Initial Time

Start of the measurement interval (h)

01000

Final Time

End of the measurement interval (h)

0.11000

Results

Doubling Time

—

Growth Rate (μ)

—

1/h

Growth Curve

N(t) = N₀ · e^(μ·t)

Fundamentals & Explanation

Exponential growth

N_t = N_0 \cdot 2^{t/T_d}

Doubling time

T_d = \frac{(t_f - t_0) \cdot \ln(2)}{\ln(N_t / N_0)}

Growth rate

\mu = \frac{\ln(N_t / N_0)}{t_f - t_0}

The doubling time (T_d) is the period required for a cell population to double its size during the exponential phase (log phase) of growth.

A continuous exponential growth model is assumed: every cell divides at a constant time interval, and there is no nutrient limitation or metabolic waste accumulation.

The specific growth rate (μ) is related to T_d by: μ = ln(2) / T_d. A higher μ indicates faster growth.

Doubling time varies considerably across organisms: from ~20 min (E. coli) to ~24–48 h for mammalian cell lines.

Valid only during the exponential phase. Not applicable during the lag, stationary, or death phases.

Doubling time — Wikipedia