Sources, definitions and calculations
Moving digits are modelled estimates, not a live census. Geographic definitions and reference years matter as much as the numbers.
Source layers
| Dataset | Used for | Limitation |
|---|---|---|
| World Bank Indicators | Country population, demographic indicators and history | Indicators have different reference years and are revised. |
| UN WPP 2024 | Long-run population and medium-scenario projections | 2024 onwards here is projection, not observation; a different vintage from World Bank. |
| UN WUP 2025 | Urban-centre populations and trajectories | Built-up urban centres are not administrative municipalities. |
| GeoNames | Place records and administrative units | A modification date is not a census date; population dates are often unavailable. |
| HYDE / Gapminder via Our World in Data | Pre-1950 reconstructions | Historical modelling, not census precision. |
Population basis
Province, administrative settlement and UN urban centre are different geographies. Each city page states which figure drives its headline, ratios and same-definition rankings. Separate figures are context, not interchangeable estimates. A settlement coordinate does not establish containment within an urban centre.
Live projection
Where explicitly used: P(t) = P0 × exp(r × elapsed years). The page states its base, model anchor and annual rate. Country growth is not a measurement of local growth. Missing dates remain unknown; a modelling anchor must not be interpreted as an observed census date.
Birthdays and stories
The birthday calculator interpolates annual mid-year population anchors; annual birth/death rates support modelled cumulative flows. Your World Story uses annual reference values, not an invented exact-day count. It marks unavailable observations rather than substituting zero. AI-authored passages are selected from a prewritten local library; numbers come from calculations, never generated text.
Projection is not destiny
UN medium projections are scenarios, not individual predictions. Life expectancy at birth describes a population and period; it does not forecast your remaining lifespan.
Known gaps
Istanbul has 39 reference-confirmed districts in the bundled list, but only 38 retained district population values; Büyükçekmece's district population is unknown. Membership coverage does not imply independently verified population coverage. Other places may have incomplete divisions or mixed-year observations.
Sources and reuse
- World Bank — observe indicator-specific terms.
- UN Population Division — cite dataset and release.
- GeoNames — attribution under CC BY 4.0.
- Our World in Data — check underlying source terms.