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