Enter the transmissibility, rate of contact, and duration into the calculator to determine the basic reproduction number, R0.

R0 Formula

The following formula is used to calculate the basic reproduction number:

R0 = t*c*d

• Where R0 is the basic reproductive number
• t is the transmissibility (infections per contact)
• c is the rate of contact (contact per time)
• d is the total time of infectiousness (time per infection)

R0 Definition

What is R0?

R0 is a symbol used to denote the basic reproductive number of an infection. This value represents the total number of expected secondary cases produced by a single infection in a completely susceptible population.

Basic Reprodoction Number Example

How to calculate R0?

1. First, determine the transmissibility of the infection/disease.

For this example, the transmissibility is .75 infections per contact.

2. Next, determine the rate of contact.

For the problem, the rate of contact is 4 contacts per hour.

3. Next, determine the total time of infectiousness.

In this case, the infectiousness lasts for 6 hours.

4. Finally, calculate R0.

Using the formula above, the basic reproduction number is calculated as:
R0 = t*c*d
R0 = .75*4*6
R0 = 18