Mortality Rate Calculator

Mortality rate = deaths during a given time period / size of the population among which the deaths occurred x multiplier. The CDC (Principles of Epidemiology, Lesson 3, Table 3.4) gives the crude mortality rate as (total deaths / mid-interval population) x 1,000 or x 100,000. For example, 2,419,921 deaths in a population of 290,809,777 gives 832.13 deaths per 100,000 population.

Their denominators are different. The mortality rate divides deaths by the population, so it measures how often death occurs in the population. The case-fatality rate divides deaths by diagnosed cases of the disease (x 100), so it measures lethality among the ill. A disease can have a low mortality rate (few deaths in the population) but a high CFR (most people who get it die).

Incidence counts NEW CASES per person-time at risk; mortality counts DEATHS per population. Incidence measures how fast a disease is occurring; mortality measures how often death occurs. See the Incidence Rate Calculator for the person-time rate, cumulative incidence and rate ratios.

Crude mortality uses all deaths over the whole population (per 1,000 or 100,000). Cause-specific mortality narrows the numerator to deaths from one cause, still over the whole population (usually per 100,000). Proportional mortality divides deaths from one cause by deaths from ALL causes (x 100) — it shows the relative importance of a cause, not the risk of dying from it.

The CDC uses both 1,000 and 100,000 for most mortality measures; cause-specific rates are usually reported per 100,000. The multiplier only rescales the number for readability — 8.32 per 1,000 = 832 per 100,000. State the multiplier you used so readers can compare.

No — a CFR above 100% is impossible and signals a data problem: more deaths than diagnosed cases. Usually the deaths were counted from a larger or different group than the cases (for example, deaths that include earlier outbreaks divided by this week's cases). This calculator rejects deaths > cases and asks you to check the inputs.

The infant mortality rate = deaths among children under age 1 / number of live births x 1,000, usually per year. The CDC notes it is technically a ratio rather than a rate, because some of the deaths in the numerator occurred among children born the previous year, who are not in the denominator. It is widely used to compare health status between populations.

Only with caution. Crude rates reflect the population's age structure: a country with an older population will have a higher crude mortality rate even with the same health conditions. The CDC illustrates this with Alaska vs Florida — use age-specific or age-adjusted rates for fair comparisons.

Strictly speaking this is a case-fatality rate: among diagnosed cases, what share died. For example, 10 deaths among 12 diagnosed pneumonic plague cases gives a CFR of 10 / 12 x 100 = 83.33%. The WHO notes pneumonic plague is almost always fatal when left untreated, while bubonic plague has a CFR of 30% to 60% untreated — antibiotics are effective when given early. These figures describe lethality among the ill, not the death rate in the general population.

No. It is an educational calculator for standard epidemiologic measures of mortality in populations, using the definitions from the CDC's Principles of Epidemiology. It does not diagnose, predict any individual's outcome, or replace professional epidemiologic analysis.