Mortality Rate Calculator: Crude, Specific, Infant, Maternal and Proportionate Mortality
Calculate a death rate per 1,000 or 100,000 people (crude, cause-, age- or sex-specific), infant, neonatal and maternal mortality, or proportionate mortality, with a 95% confidence interval.
How it works
Death rate = deaths ÷ mid-period population × 10ⁿ (per 1,000 or 100,000) · Specific rate: deaths and population of the same cause, age or sex group · Infant (neonatal, postneonatal) mortality = deaths under 1 year (under 28 days, 28 days–1 year) ÷ live births × 1,000 · Maternal mortality = pregnancy-related deaths ÷ live births × 100,000 · Proportionate mortality = deaths from a cause ÷ all deaths × 100% · 95% CI: exact Poisson for fewer than 100 deaths, else rate × (1 ± 1.96 ÷ √deaths)
A mortality rate tells you how often death occurs in a defined population over a set period. Following the CDC’s epidemiology course, each measure has its own numerator, denominator and usual multiplier. The crude death rate uses all deaths and the mid-period population, typically per 1,000 or 100,000. A specific rate restricts both the deaths and the population to the same cause, age group, sex or combination. Infant, neonatal and postneonatal rates divide by live births per 1,000, and maternal mortality per 100,000 live births. Proportionate mortality is the share of all deaths due to one cause. Because death counts follow a Poisson distribution, the calculator also gives a 95% confidence interval: exact Poisson limits for fewer than 100 deaths and the normal approximation above that, and it warns when fewer than 20 deaths make a rate unreliable. For several years of data, enter the period length to get an annual rate, and enter a reference rate to see how yours compares. It differs from the Case Fatality Rate calculator, which divides deaths by people with a disease, and from the Incidence Rate calculator, which counts new cases per person-time.
Worked example
In the United States in 2003 there were 2,419,921 deaths and a mid-year population of 290,809,777. The crude death rate is 2,419,921 ÷ 290,809,777 × 100,000 = 832.1 per 100,000 (8.32 per 1,000), or one death per 120 people. With that many deaths the 95% interval is narrow: 2,419,921 ± 1.96 × √2,419,921 gives 831.1 to 833.2 per 100,000. Infant mortality that year was 28,025 deaths ÷ 4,089,950 live births × 1,000 = 6.85 per 1,000.
Sources: CDC: Principles of Epidemiology, Lesson 3 Section 3 — Mortality frequency measures · Omni Calculator: Mortality rate (crude, infant, maternal, proportional)
Frequently asked questions
How do you calculate a mortality rate?
Divide the number of deaths in a period by the population at risk at the middle of that period, then multiply by 1,000 or 100,000. For example, 108,256 accident deaths in a US population of 290.8 million is 108,256 ÷ 290,809,777 × 100,000 = 37.2 deaths per 100,000.
What is the difference between crude and age-specific mortality?
The crude rate counts all deaths in the whole population, so it depends on how old the population is. An age-specific rate uses only deaths and population in one age group, such as 25–44 year olds, so it can be compared between places with different age structures.
How is infant mortality rate calculated?
Deaths of children under 1 year divided by live births in the same year, times 1,000. In 2003 the US had 28,025 infant deaths and 4,089,950 live births, an infant mortality rate of 6.85 per 1,000 live births.
What is the difference between mortality rate and case fatality rate?
A mortality rate divides deaths by the whole population at risk, so it reflects how common a disease is as well as how deadly. A case fatality rate divides deaths by the people who have the disease, so it measures how deadly the disease is once someone has it.
Why does the calculator show a confidence interval?
Deaths are random events, so the same underlying risk can produce more or fewer deaths in a given year. With 10 deaths in 50,000 people the rate is 20 per 100,000, but the 95% interval runs from 9.6 to 36.8, so a small area’s rate can swing widely. Rates based on fewer than 20 deaths are usually flagged as unreliable.
Related calculators
For education and public-health practice. Rates are only as good as the death counts and population figures you enter; check definitions (for example, what counts as a maternal death) against the official source before publishing or comparing rates.