COVID19 & K Factor

Posted on 2020 March 18th.

COVID19 has trampled the Philippine economy and the question remains - When will this end? Hence, I would like to introduce the K Factor, or K Value, or Viral Coefficient used by Epidemiologists to determine if something is viral or not.

In short the K Factor Formula is:

K = I x R


I = Invitations or the number of people exposed.

R = Conversion Rate or the number of people infected for every total number of people exposed.

The simplest way I can interpret the results is this way:

If the result is less than 1, then it is not viral.

If the result is exactly 1, it is still not viral but still dangerous to break out into something viral so keep an eye on this.

if the result is more than 1, then it is viral. Even if the K or result is slightly above 1 like 1.000001, it is still considered viral.

Let's use the data provided by

As of March 18, 2020 at 6:06 PM, there are:

259 PUI or Person Under Investigation

655 Cases Tested Negative

202 Confirmed Cases

17 Deaths

7 Recovered

Let's find I or the number of people exposed by adding the PUI(259), Cases Tested Negative(655) and Confirmed Cases(202) which is 1,116.

Next, let's find R or Conversion Rate by dividing the Confirmed Cases(202) by the I(1,116) which results to 0.18 or 18%.

Now let's plug in the values to find K:

K = I x R

K = 1,116 x 0.18

K = 200.88

As explained earlier, any value above 1 is viral which means 200.88 is viral. In other words, for every 1,116 people exposed, 18% gets infected. Then the next 1,116 people exposed to the newly infected 18% will infect another 18%.

K Factor is just a start and does not really give you all the answers but it gives you an idea how viral something is. Take note that there is a Compounding Interest effect in place at a given Cycle Time or Period of Time.

You may use the K Factor to closely monitor if the coast is clear or not. Remember the value of K should be less than 1 to know that the coast is clear and our lives are back to normal.

I hope this short blog helped you stay calm and do the right thing during this crisis.