The Centers for Disease Control and Prevention says the safest Thanksgiving is celebrated only with people in the same household, no visitors allowed.

Unfortunately, not everyone will follow that guidance. So what’s your risk of getting COVID-19 if you celebrate Thanksgiving at a gathering of 10, or even 15 people? Georgia Institute of Technology scientists developed an interactive map that tells you.

This tool allows you to select how many people will be in the same room and, based on the level of cases in your county, calculates the probability that at least one person will get COVID-19 and possibly infect others. (By default, the calculations assume there are five times more cases in a given area than are being reported.)

In Connecticut, here are the chances in each county of being infected in Thanksgiving parties of 10 and, in parenthesis, 15 people:

  • Hartford: 20 percent (28 percent).
  • Tolland: 16 percent (23 percent).
  • Middlesex: 18 percent (26 percent).
  • New Haven: 23 percent (32 percent).
  • Windham: 16 percent (22 percent).
  • New London: 14 percent (21 percent).
  • Litchfield: 19 percent (27 percent).
  • Fairfield: 24 percent (34 percent).

Even bigger parties, naturally, create even higher risks. In Fairfield County, for example, a 20-person party presents a 42 percent chance of infection. Want to go to a 50-person blowout? Then you have a 50 percent chance of infection.

Elsewhere in the country, it’s even riskier. If you’re planning to attend a 10-person Thanksgiving celebration in Walsh, N.D., you have a 76 percent chance of getting COVID-19.

“Conventional Thanksgiving is a high-risk activity,” says Keith Grant, Hartford HealthCare‘s Director of Infection Prevention. “You should identify risk factors for each guest, whether they have comorbidities or other risk factors. It’s risk stratification.”