Specific Growth Rate Calculator (µ)
By Santaji GadepatilinUpdated October 27, 2026
per hour
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Type in any field to change it. Press × on a value to calculate that field instead.
How to use this calculator
Enter two biomass or OD readings and the time between them. The specific growth rate (per hour) and doubling time are calculated.
Formula
µ = ln(X₂ ÷ X₁) ÷ Δt Td = ln 2 ÷ µ
Example
OD600 rises from 0.1 to 0.8 in 6 hours:
- µ = ln 8 ÷ 6 = 0.3466 h⁻¹
- Doubling time = 2.0 h
Frequently asked questions
What is specific growth rate?
The rate of increase in biomass per unit of biomass, µ = ln(X₂/X₁) ÷ (t₂ − t₁), usually in h⁻¹.
How is it related to doubling time?
Doubling time = ln 2 ÷ µ.
Can I use optical density?
Yes, OD600 readings in the linear range of the spectrophotometer are proportional to biomass.