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

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## 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?

**First, determine the transmissibility of the infection/disease.**For this example, the transmissibility is .75 infections per contact.

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

**Next, determine the total time of infectiousness.**In this case, the infectiousness lasts for 6 hours.

**Finally, calculate R0.**Using the formula above, the basic reproduction number is calculated as:

R0 = t*c*d

R0 = .75*4*6

R0 = 18