CFR letalidade %
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
The CFR (Case Fatality Rate) calculator estimates the proportion of deaths relative to the total number of confirmed cases of a disease. The formula is (number of deaths ÷ confirmed cases) × 100. This metric is crucial for assessing the severity of infectious diseases like COVID-19 or influenza in a specific region or timeframe.
To use the tool, input the number of deaths and confirmed cases. The result, expressed as a percentage, helps compare lethality across populations or track disease progression over time. For example, 500 deaths in 100,000 cases yield a CFR of 0.5%.
Accuracy depends on data quality, testing availability, and population characteristics. Incomplete or underreported data can skew results. Additionally, CFR does not account for asymptomatic or mild cases that may not be documented.
This tool is valuable for healthcare professionals, public officials, and researchers analyzing infectious disease impacts. Always interpret results cautiously alongside other metrics, such as transmission rates and healthcare system capacity.
Frequently asked questions
Why is CFR presented as a percentage?
Percentages make relative risk easier to understand. For example, 2% is more intuitive than 0.02 when assessing severity.
What data should I use to calculate CFR?
Use official death and confirmed case counts from the same source and timeframe to ensure accuracy.
Can CFR be compared across different countries?
Yes, but factors like population age, treatment access, and data quality must be considered for fair comparisons.
Why might CFR underestimate lethality in some cases?
In early outbreaks, asymptomatic cases may not be documented, artificially inflating the death proportion.
When should I update the calculator's data?
Update whenever new official case or death records are published to maintain calculation accuracy.