Cell Doubling Time Calculator
Enter a starting count, a later count and the time between them. The calculator returns the number of doublings, the doubling time and the exponential growth rate.
How to calculate doubling time
- Enter the starting cell or colony count.
- Enter the later count and the time that passed between the two readings.
- Read the number of generations, the doubling time and the growth rate constant.
Examples
Bacterial culture
1000 to 8000 in 6 hours
3 doublings, 2 h doubling time
Hundredfold growth
1e6 to 1e8 in 10 hours
6.6439 doublings, 1.5051 h doubling time
Frequently asked questions
What is doubling time?
Doubling time is how long an exponentially growing population takes to double in number. A shorter doubling time means faster growth.
How is doubling time calculated?
Find the number of doublings as log base 2 of the final count over the initial count, then divide the elapsed time by that number of doublings.
What time unit does the result use?
Whatever unit you enter for the elapsed time. If you enter hours, the doubling time is in hours and the growth rate is per hour; minutes work the same way.
What is the growth rate constant?
It is the exponential rate, equal to the natural log of 2 divided by the doubling time. It is the constant in the model count equals initial times e to the rate times time.
Why must the final count exceed the initial count?
The model describes growth, so the population must increase. Equal or smaller counts give zero or undefined doublings, which this calculator rejects.
Related tools
Half-Life Calculator
Solve radioactive decay with N = N0 times one half raised to t over T. Enter any three of initial, remaining, half-life and time to find the fourth.
Punnett Square Calculator
Build a monohybrid Punnett square from two parent genotypes. See the 2x2 cross grid, genotype ratios like 1:2:1 and the dominant to recessive split.
Molarity Calculator
Calculate molarity in mol per litre and solve for moles, volume or concentration. Find moles from mass and molar mass, then get the missing value.
555 Timer Calculator
Calculate 555 timer astable frequency, period, high and low times and duty cycle from R1, R2 and the timing capacitor. Free oscillator design helper.
Absolute Humidity Calculator
Calculate absolute humidity in grams of water vapor per cubic meter from air temperature and relative humidity. Fast, free and works in your browser.
Allele Frequency Calculator
Find allele frequencies from genotype counts. Enter the number of AA, Aa and aa individuals to get the A and a allele frequencies and allele totals.