The birth rate is typically the rate of births in a population over time. The rate of births in a population is calculated in several ways: live births from a universal registration system for births, deaths, and marriages; population counts from a census, and estimation through specialized demographic techniques. The birth rate (along with mortality and migration rate) are used to calculate population growth.
The crude birth rate is the number of births per 1,000 people per year. Another term used interchangeably with birth rate is natality. When the crude death rate is subtracted from the crude birth rate, the result is the rate of natural increase (RNI). This is equal to the rate of population change (excluding migration).
The total (crude) birth rate (which includes all births)—typically indicated as births per 1,000 population—is distinguished from an age-specific rate (the number of births per 1,000 persons in an age group). The first known use of the term "birth rate" in English occurred in 1859.
In 2012 the average global birth rate was 19.15 births per 1,000 total population, compared to 20.09 per 1,000 total population in 2007.