Demography
Demography Lab
Set how many children women have, how long people live and how many people move, then watch a population pyramid change over the next 150 years.
Population pyramid
What happens next
Very lowVery high
40 (women)90 (women)
Men are assumed to live 4 years less than women.
People leavePeople arrive
Key numbers
Over the next 150 years
The dot marks the year you picked above.
Population (millions)
Growth rate (% per year)
Rates calculator
Enter one year of data for any population.
- Crude birth rate = births / population × 1,000
- Crude death rate = deaths / population × 1,000
- Natural increase = (births − deaths) / population, shown as a percent
- Growth rate = (births − deaths + net migrants) / population
- Doubling time = ln 2 / ln(1 + growth rate), or about 70 / growth rate in percent
Words used on this page
| TFR | Total fertility rate: the average number of children a woman would have if she lived through all the childbearing ages at today's rates. |
| Replacement level | The TFR at which each generation exactly replaces itself, about 2.1 where few children die. It is higher where more die young. |
| Life expectancy | The average number of years a newborn would live at today's death rates. |
| Crude birth and death rates | Births and deaths in a year for every 1,000 people. |
| Natural increase | Births minus deaths. Migration is not included. |
| Dependency ratio | People under 15 plus people 65 and over, for every 100 people aged 15 to 64. |
| Median age | The age that splits the population into a younger half and an older half. |
| Population momentum | A young population keeps growing for decades after fertility falls, because many young people are still to have children. |
The starting populations and the projection are illustrative models, not data for a real country.