Bacterial Growth Rate Calculator

Work out bacterial growth rate instantly with clear inputs, formula shown and shareable results.

About Bacterial Growth Rate Calculator

Fits exponential growth through two cell counts to give the specific growth rate, the number of generations and the doubling time.

Formula

Exponential growth

mu = ln(N/N0) / t; generations = log2(N/N0); doubling time = t / generations

Worked example

With the default values below, Bacterial Growth Rate Calculator returns Specific growth rate of 0.69315. Change any input above and every figure here is recalculated in your browser.

Inputs used

Initial cell countaccepts 1–1,000,000,000,000 cells/mL: 100,000 cells/mL
Final cell countaccepts 1–1,000,000,000,000 cells/mL: 800,000 cells/mL
Elapsed timeaccepts 0.05–500 h: 3 h

Results

Specific growth rate: 0.69315 per hour
Doubling time: 1.0000 h
Generations elapsed: 3.000
Fold increase: 8.000

Step by step

1Values used
2Exponential growth
3Specific growth rate= 0.69315 per hour
4Doubling time= 1.0000 h
5Generations elapsed= 3.000
6Fold increase= 8.000

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

When does this apply?

Only during the exponential phase; lag and stationary phases break the exponential assumption.

What is a typical doubling time?

About 20 minutes for E. coli in rich medium, but hours to days for slow-growing organisms such as mycobacteria.