\( \displaystyle \text{Birth Rate} = \frac{\text{Number of births in a given period}}{\text{Total population in that same period}} \times 1000 \) – Interpreted as the number of births per 1,000 inhabitants.

\( \displaystyle \text{General Fertility Rate (GFR)} = \frac{B}{\text{NF}15-49} \times 1000 \) – Where B is the total number of births in a given period and NF15-49 is the female population aged 15 to 49 during that same period. The factor 1000 expresses the rate per 1,000 women of reproductive age.

\( \displaystyle \text{Mortality Rate} = \frac{\text{Number of deaths in a given period}}{\text{Total population in that same period}} \times 1000 \) – Also called the Crude Death Rate; indicates the number of deaths per 1,000 inhabitants.

\( \displaystyle \text{Life Expectancy at birth} = \sum_{x=0}^{\omega} \Bigl(\frac{\ell_x}{\ell_0}\Bigr) \) – Where \(\ell_x\) is the number of survivors at exact age \(x\) in a hypothetical cohort, and \(\ell_0\) is the initial size of that cohort. This represents the mean number of years a newborn is expected to live, assuming current mortality rates remain constant.

\( \displaystyle \text{Natural Growth Rate} = \frac{(\text{Births} - \text{Deaths})}{\text{Total population}} \times 100 \) – Expressed as a percentage of population growth (or shrinkage) disregarding migration.

\( \displaystyle \text{Annual Growth Rate} = \frac{(\text{Births} - \text{Deaths} + \text{Immigrants} - \text{Emigrants})}{\text{Total population}} \times 100 \) – Also expressed as a percentage, including both natural increase and net migration.

Population Pyramids: Not strictly a formula, but a horizontal bar graph that illustrates the distribution of different age groups (cohorts) in a given year, with males on the left and females on the right.