Rate of natural increase

In demography and population dynamics, the rate of natural increase (RNI), also known as natural population change, is defined as the birth rate minus the death rate of a particular population, over a particular time period. It is typically expressed either as a number per 1,000 individuals in the population or as a percentage. RNI can be either positive or negative. It contrasts to total population change by ignoring net migration.

This RNI gives demographers an insight into how a region's population is evolving, and these analyses can inform government attempts to shape RNI.

Suppose a population of 5,000 individuals experiences 1,150 live births and 900 deaths over the course of one year.

To show the RNI over that year as a percentage, the equation would be

           (1,150 – 900) ÷ 5,000 = 0.05 = +5%

To show the RNI as a number per 1,000 individuals in the population, the equation would be

           (1,150 – 900) ÷ (5,000/1,000) = 250 ÷ 5 = +50

It can also be shown as natural births per 1,000 minus deaths per 1,000