This calculator lets you estimate COVID risk and find effective safety measures for customizable situations. Examples: how risky is a trip to my grocery store? What's the safest way to see a friend? How much would it help to wear a better mask at my workplace?

We created the concept of the "microcovid" as a new quantitative unit for risk. One microCOVID is a one-in-a-million chance of getting COVID.

An activity thatā€™s 20,000 microCOVIDs means that you have a 2% risk of getting COVID every time you do it. An activity thatā€™s 20 microCOVIDs (or 0.002%) is relatively safe, as you could do it every week for a year and still have only accumulated about a 0.1% chance of getting COVID.

You may decide that you're comfortable with taking on a certain amount of COVID risk. You can think about this amount of risk that you're willing to take on as a "risk budget".

For most healthy people who are not in contact with vulnerable groups, we think an annual risk budget of a 1% chance of catching COVID is reasonable - that's a budget of 10,000 microCOVIDs a year. In order to meet this budget, you'd need to stick to a maximum of about 200 microCOVIDs a week.

If you'd like to watch a video walkthrough of how to use the calculator, click here.

see all updatesā€¦

Calculate approximate risk of contracting COVID

Step 1: Enter COVID rate

Currently there is no consistent reporting on COVID prevalence in the US. Please use the buttons or the sliders below to set a COVID level based on your impression of whether cases are low or high right now.

It may help to look at wastewater data: Choose an area new you, set the graph to "all time," and see how levels now compare to past highs and lows.

Reported prevalence: 0.00%
Adjusted prevalence: 0.00%

Prevalence Presets

Low
Medium
High
Extreme
Warning: if you are entering cases per 100,000, this field should be set to 100,000
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Step 2: Describe the scenario

Nearby people

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Very Low Risk
0.2% of your weekly risk budget
~0.4 microCOVIDs each time (probably between: 0.1 to 1.1)
Model last updated on 1/4/2022. See all updatesā€¦

Calculation:

(1 Person Risk) x (60% Activity Risk) x (1 person)
= ~0.4 microCOVIDs each time you do it
(probably between: 0.1 to 1.1)

Calculation Steps:

  1. Person Risk: 1-in-a-million chance
    First, we calculate that each other person in this area has a 1-in-a-million chance of currently having COVID.
  2. Activity Risk: 60% chance
    Next, we calculate the risk of the activity. A person doing this activity with COVID-19 would have a 60% probability of transmitting it to you. (NOTE: capped this number.)
  3. Number of people: 1 person
  4. Total risk: 0.4-in-a-million (0.00004%)
    Finally, we multiply Person Risk, Activity Risk, and the number of people to get the total result of roughly 0.4-in-a-million (0.00004%) chance of getting COVID from this activity with these people each time you do it.
  5. Frequency: each time you do it
    Since this is a one-time interaction, the result is shown as microCOVIDs each time you have this interaction. If you do this activity many times in a week, each time you do it, it will count against your weekly budget. If you do this activity many times with the same people each week, enter them as "Living/staying with a partner/spouse" to see what the maximum transmission rate is per week.
  6. Probably between: 0.1 and 1.1 microCOVIDs
    We believe with roughly 90% confidence that the actual risk falls between these two values. See our uncertainty estimation.

How much of this can I do given my risk budget?

  • Budget available: 200 microCOVIDs per week
    You selected an annual budget of a 1% chance of getting COVID per year (10,000 microCOVIDs). That equates to a weekly budget of 200 microCOVIDs per week.
  • Budget used: 0.2% of your weekly risk budget each time you do it
    This interaction uses 0.2% of your weekly risk budget. This amount of your budget will be used each time you do it.

How to reduce risk:

These may or may not apply to your activity.
  1. MODify your activities (make them Masked, Outdoors, Distanced)
  2. Wear the best mask you can get! Learn more about masks in our blog post.
  3. Visit public places during less crowded hours
  4. Reduce shopping trips by doing one trip for multiple people, using delivery services, or shopping online
  5. If this activity is with friends, encourage them to not come if they or any of their close contacts are feeling unwell
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0.1% chance of COVID per year (20 microCOVIDs per week) Suggested if you or your close contacts are more vulnerable to COVID.
1% chance of COVID per year (200 microCOVIDs per week) Suggested for healthy people NOT in close contact with more vulnerable people.
3% chance of COVID per year (600 microCOVIDs per week). If you are healthy and prefer to live a riskier lifestyle AND everyone you live with / share air with is willing to do the same.
10% chance of COVID per year (2000 microCOVIDs per week) Use this if you can't avoid risk, but still want to make smart choices. Remember: if you get COVID, you may give it to anyone you come in contact with. Try taking the smallest risk you can to protect them.