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COVID-19

COVID-19
Risk Calculator

Gain an understanding of how to reduce the risk of COVID-19 transmission in indoor environments using affordable control strategies.

Harvard T.H. Chan School of Public Health

Important notes about this tool

This tool is primarily designed to provide insight into the effectiveness of various control strategies and impacts of human behaviors on infection risks in indoor environments rather than providing exact estimates of absolute risk. It is based on several super-spreading events, which may result in overestimates of the risk that people face in typical indoor environments.

Please note that the risk estimates determined by this tool:

  • Assume at least one infector and one susceptible individual are present in the indoor environment,
  • Assume the infector(s) is/are at their peak infectivity,
  • Do not consider different levels of infectivity of the new variants of SARS-CoV-2,
  • Do not consider variation in individuals' susceptibility (e.g., age, underlying diseases, and vaccination status change the susceptibility of individuals),
  • Assume that there is no residual risk of transmission from activity that occurred prior to the scenario input to the calculator, and
  • Are not applicable to children.
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Calculate The Impacts of Control Measures on COVID-19 Transmission

As we continue to navigate the COVID-19 pandemic, people around the world often ask themselves the same question as they head into various buildings and scenarios: What changes can we make to reduce the risk of COVID-19 transmission? To help provide some insight into this question, the Harvard Healthy Buildings Program has released this beta version of the ASIMI (Aerosol and Surface Interaction Model for Infectious diseases) Tool for calculating the risk of COVID-19 transmission, which estimates potential infection risk based on several factors and transmission pathways. This tool is based on our peer-reviewed paper in the Proceedings of the National Academy of Sciences of the United States of America.

1. Rooms & People

Basic
Advanced
Small
Large
m2
ft.2
m
ft.
1 hour
10 hours
hours
m.3/hour
cfm/hour
Help estimating breathing rate
person(s)

2. Risk Reduction

Basic
Advanced
Not Likely
Very Likely
%
%
%
Poor
Excellent
%
% efficient
touch/hr.
touch/hr.
touch/hr.
Poor
Excellent
%
%
None
Perfect
% of total time
Windows Closed
Windows Open
1/hr
Low
High
1/hr
%
%
%
1/hr
Poor
Excellent
1/hr
1/hr

Results

Configure the calculator settings and then click the button below to generate your risk report.

Running simulation...

Program Error

There was an internal error with the calculator.
Please try again later.

Input Error

There was an error with some of your inputs.
Please check them and try again.

Results

The scenario data you've entered result in the following risk profile:

Estimated Transmission Risk

≤ 1% 10% 100%

Relative Transmission Contribution

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