Case Fatality Rate Calculator
Case fatality rate with confidence interval and CFR among resolved cases.
Enter your values to see the result.
CFR is a proportion of cases, not of the population. It overstates severity when mild cases go uncounted and understates it early in an outbreak, before outcomes are known. Confidence intervals use exact (Clopper–Pearson or Poisson) methods. Rates are only comparable between populations with similar age structures unless you standardize them.
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- Mortality Rate Calculator — Calculate population death rates.
- Attack Rate Calculator — Measure how many fell ill.
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Clear instructions
Find steps, examples and limitations below.
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How to use the Case Fatality Rate Calculator
Case fatality rate with confidence interval and CFR among resolved cases.
- 1 Enter the deaths among cases and the number of cases.
- 2 Optionally enter the number who recovered.
- 3 Read the CFR, the CFR among resolved cases and the intervals.
Example and practical tips
36 deaths among 1,200 confirmed cases is a case fatality rate of 3% (95% CI 2.11% to 4.13%).
Frequently asked questions
Is CFR the same as the mortality rate?
No. CFR divides deaths by cases; the mortality rate divides deaths by the whole population.
Why does CFR change during an outbreak?
Recent cases have not had their outcome yet, and mild cases are often missed. The resolved-case CFR corrects for the first problem.
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