We designed this calculator to help people understand to importance of wearing masks in public. It tells you how your individual actions may limit the spread of COVID-19.
Do you wear a mask?
Yes
Mask material
Cotton
Cotton masks have a filtration efficiency of about 80% [1].
Initial reproduction number R₀
COVID-19 has an R₀ of roughly 2.4 to 4.0, with the best current estimate being 2.5 if no restrictions were introduced (e.g. wearing a mask). It means that each new person spreads the disease to about 2 - 4 people on average. Our calculator assumes an average incubation period of 5 days.
Percentage of people that wear masks
%
Results
After two weeks, your individual actions may protect up to 20 people from an infection. That results in 1 saved life ❗ (if we consider the COVID-19 mortality rate).
Thanks, you help bring down the reproduction number, R₀, to 0.1 ❤️ To stop the epidemic, we need the value of R₀ to be less than 1.

Encourage others to join you in your mask wearing. Together we can beat this epidemic!
Disclaimer:
The blue line on this chart shows how many people you might infect if 100% of people wear masks. The effect of scale is important when considering the spread of the disease.
The below chart shows the influence of the mask filtration efficiency (x-axis) and percentage of people that cover their mouth and nose with masks (y-axis) on the effective reproduction number R₀.
The colors mean:
• dark blue - R₀ is lower than 1. You should aim to be here!
• light blue - R₀ is greater than 1.
• yellow - R₀ is greater than 1.3.
• orange - R₀ is greater than 1.9.
The red pointer shows where are you now with your presets. Are you doing everything you can to prevent the spread of the epidemic? 😷 See how the social distancing helps fighting the epidemic.
Professor from the UCSF, Peter Chin-Hong, MD, recommends the Three W’s to ward off COVID-19, which are: wearing a mask, washing your hands, and watching your distance. But, of the three, the most important thing is wearing a mask, he said. So, don't risk your and others lifes and cover your mouth and nose!

The COVID-19 pandemic is still an ongoing battle and face-masks have been proposed as one of the non-pharmaceutical interventions to help fight the novel coronavirus. While many governments are making masks mandatory (including the UK), some countries are still struggling to accept masks as a protective measure. Almost 30% of Americans are using a mask "sometimes", "rarely" or "never", while one of the models suggests that if everyone in the US wore a mask in public, 33,000 lives could be saved over the next 3 months!

But how do masks work? Can they be dangerous to our health? These are the questions on millions of minds right now, so we decided to create the face mask calculator to help to answer them. We hope to raise public awareness and encourage people to wear face masks to protect themselves and others. Check how many lives you can save! 🦸🏻

Can wearing a mask save lives? Science behind face masks

In an editorial published in July 2020, the Centers for Disease Control and Prevention (CDC) reviewed the latest science regarding face masks. The results are straightforward - cloth face coverings are a critical tool in the fight against COVID-19. They can reduce the spread of the disease, particularly when used universally within communities. The novel coronavirus transmits primarily via respiratory droplets, where presymptomatic and asymptomatic individuals can also spread the disease.

Therefore, reducing the spread requires two things:

  1. Limiting the contact of infected people through physical distancing (social distancing).

  2. Reducing the probability of transmission per contact with an infected person (through face masks).

Research studies [1], [2] show that wearing a face-mask is related to the second subpoint, as covering your face will reduce the transmission of infected droplets.

The current position of the research on wearing a mask is as follows:

  • High use of face-masks is effective at reducing the spread of the virus;

Important fact: If efficacious face-masks are used (such as surgical masks, with an estimated efficacy of 70%) in public, it could lead to the elimination of the pandemic in the US (if at least 80% of Americans use such masks in public consistently).

  • Combining face-masks and social-distancing is more effective in COVID-19 control;

  • The decreased transmissibility due to mask wearing could substantially reduce the death toll and economic impact;

  • Due to some shortages of medical masks, experts encourage the use of cloth masks (also home-made); and

  • Public officials and governments should implement appropriate regulation and strongly encourage people to use face masks in public.

Types of masks and protection levels

For most of us, face masks are a novelty, so how do you decide which mask is the best for you and how long it can last? We have created a coronavirus mask calculator to help you answer those questions, although you can find some key information about the types of masks below:

  1. Cloth masks:
Coronavirus Mask Calculator: cloth mask
  • they are cheap and widely accessible;
  • they block only some of virus particles present in exhaled air (they do stop fluids from coughs and sneezes though);
  • they can be re-used many times (providing that they are washed frequently and correctly!); and
  • the CDC recommends them as the best choice for everyday purposes.
  1. Surgical masks:
Coronavirus Mask Calculator: surgical mask
  • they filter only some of the virus particles;
  • they require frequent changing; and
  • they are not reusable.
  1. N95/N99 respirators and masks with N95/N99 filters:
Coronavirus Mask Calculator: mask with N95 filter
Coronavirus Mask Calculator: other FFRs
  • they block up to 99% of viral particles;
  • those masks are significantly more expensive than cloth and surgical masks; and
  • filters need to be changed according to the recommendations to stay effective.

How does the mask calculator work?

We created the face mask calculator to help people understand the importance of wearing masks in public. It will tell you how your individual actions may limit the spread of COVID-19.

  1. Answer the question "Do you wear a mask or not?" If you do, choose the type of the mask that you are wearing, as they have different filtration efficiencies.

  2. Choose the initial reproduction number R₀. This should be estimated for the society with no epidemic restrictions introduced, i.e., at the beginning of the pandemic. The calculator has a default value of 2.5, as the coronavirus has an R₀ of roughly 2.4 to 4.0. This means that each new person spreads the disease to about 2 - 4 people on average.

  3. In the third section, you can choose how many people correctly wear a mask.

After filling this information in, you will get the results - the estimated number of people that will be protected from the infection and the number of lives saved. All due to wearing a mask!

Play with the results to see how the number change when more and more people wear masks. We've also embedded a graph to show this information in an easier, graphic form. Maybe you will be able to convince your friends and family to become a hero? 🦸

💡 Disclaimer: remember that our calculator simulates a very complex, dynamic system in a simplified way. For example, it doesn't take into account the effect that measures such as quarantine have on the spread of coronavirus.

Myths about face masks

  1. Wearing a mask stops breathing

We could elaborate on how masks do not decrease your oxygen uptake and saturation, but this short video made by a surgeon (who always wears masks at work!) explains everything:

  1. If I'm not sick, I don't need to wear a mask

As we've mentioned earlier, presymptomatic and asymptomatic individuals can also spread the disease. Moreover, research studies confirmed that public mask wearing is most effective at reducing spread of the virus when compliance is high, so even if you are not sick, you should still wear a mask!

  1. Wearing a mask eliminates the need for social distancing

Wearing a mask is only one step in reducing the spread of COVID-19. The second one is still social distancing – try to always keep your distance in public spaces:

  • six feet;
  • 2 meters; or
  • about two arms.

How to make your own mask

The CDC recommends that you wear cloth face coverings in public setting, especially when other social distancing measures are difficult to maintain (don't forget about frequent hand disinfection!). You don't need to worry about spending a lot of money on surgical masks or masks with filters - simple cloth face masks can be made at home and they still can help prevent the spread of COVID-19!

In this link you will find all the necessary information on how to make your own face mask at home. You can choose from two different options: sewn and non-sewn face covering.

Wear a mask like Tom Hanks

If you made it to the end of this article, you should now know how important wearing a mask in a public space is. It's hard to argue that the new normal isn't inconvenient, but the facts are undeniable – wearing a face-mask can save lives. If you are still sceptical, maybe Tom Hanks will convince you! 🙃

Joanna Michałowska, PhD candidate and Dominik Czernia, PhD candidate

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