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Doubling Time Of Cases Calculator

Work out doubling time of cases instantly with clear inputs, formula shown and shareable results.

About Doubling Time Of Cases Calculator

Fits an exponential curve through two case counts to give the growth rate and the time taken for cases to double.

Formula

Doubling time

r = ln(cases end / cases start) / days; doubling time = ln 2 / r

Worked example

With the default values below, Doubling Time Of Cases Calculator returns Doubling time of 5.000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cases at the startaccepts 1–100,000,000
100
Cases at the endaccepts 1–100,000,000
400
Days between the countsaccepts 0.5–365
10

Results

Doubling time
5.000 days
Exponential growth rate
0.13863 per day
Growth per day
14.870%
Fold increase over the period
4.000

Step by step

  1. 1Values used
  2. 2Doubling time
  3. 3Doubling time= 5.000 days
  4. 4Exponential growth rate= 0.13863 per day
  5. 5Growth per day= 14.870
  6. 6Fold increase over the period= 4.000

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

Why is doubling time intuitive?

It converts an abstract growth rate into a timescale people can act on, such as bed capacity planning.

What limits its usefulness?

Reporting artefacts and changing test capacity distort case counts, so hospitalisations are often a better series.

Related Calculators

Doubling Time Of Cases Calculator – Calculate Doubling time