Event Risk Calculator
Calculate the probability of COVID-19 exposure at events and gatherings
Event Risk Assessment
Total number of people expected to attend the event
Population of your city/county/region
New confirmed cases in your area over the last 2 weeks
For reference only - check local health department data for accurate case counts
Advanced Settings
Estimates undetected cases. Research suggests 4x multiplier (80% of cases undetected).
Event Risk Assessment Results
Risk Calculation Breakdown
🛡️ Safety Recommendations
Risk Level Guide
🦠 Prevention Strategies
🎂 The Birthday Paradox
Just like the birthday paradox shows that in a group of 23 people there's a 50% chance two people share a birthday, the probability of encountering infection at events can be surprisingly high.
Understanding Event Risk Calculation
Mathematical Model
The calculator uses probability theory to estimate the likelihood that at least one person at your event is infected with COVID-19, based on local infection rates and event size.
Key Formula:
Components:
- Active Cases: New cases in last 14 days (typical infection duration)
- Hidden Multiplier: Accounts for undetected asymptomatic cases
- Population Base: Total local population for infection rate calculation
- Event Size: Number of attendees increases cumulative risk
Research Basis
The hidden case multiplier of 4x is based on epidemiological research suggesting that approximately 80% of COVID-19 infections go undetected due to asymptomatic cases and limited testing capacity.
Factors Affecting Risk:
- Duration: Longer events increase transmission opportunity
- Indoor vs. Outdoor: Ventilation significantly affects airborne transmission
- Activity Level: Speaking, singing, exercise increase aerosol production
- Demographics: Age and health status of attendees
- Preventive Measures: Masks, distancing, vaccination status
Note: This model provides statistical estimates and cannot predict actual outcomes. Individual risk varies based on many factors not captured in this simple calculation.
Related COVID-19 Risk Calculators
Data Sources and Limitations
Data Collection
- • Users must manually input local case data from health departments
- • 14-day active case window based on typical COVID-19 infection duration
- • Hidden case multiplier adjustable based on local testing capacity
- • Population data should reflect actual event catchment area
Model Limitations
- • Assumes random mixing - doesn't account for clustering
- • Doesn't include vaccination status or natural immunity
- • Static model - doesn't account for changing conditions
- • Simplified transmission model ignoring environmental factors
Recommended Data Sources: CDC COVID Data Tracker, state/local health department dashboards, WHO situation reports. Always use the most recent data available and consider local epidemiological trends.
⚕️ Important Public Health Disclaimer
FOR EDUCATIONAL AND PLANNING PURPOSES ONLY: This calculator provides statistical estimates based on simplified mathematical models and should not replace professional public health guidance. Actual transmission risk varies significantly based on numerous factors including viral variants, vaccination status, natural immunity, event characteristics, environmental conditions, and individual health factors. Results cannot predict individual outcomes or guarantee safety. Always follow current CDC, WHO, and local health department guidelines. For high-risk events or populations, consult with public health professionals. Event organizers should implement multiple layers of protection regardless of calculated risk levels. This tool does not constitute medical or public health advice and should not be used as the sole basis for event planning decisions.