This simulator uses a simple Generational Replacement Model which assumes a stable population age structure and constant mortality rates. This simplifies the effect of fertility over a generation (~30 years). In real populations, past fertility changes (like the post-war baby boom) create "population momentum," meaning actual population figures will **grow more slowly or decline more slowly** than shown here, due to the size of the current reproductive cohort. This tool isolates the long-term TFR impact once momentum is spent.

The projection assumes the selected Total Fertility Rate (TFR) remains constant for the duration of the simulation. Demographic reality is dynamic; fertility rates rarely stay static. If TFR continues to trend downward over time, the actual population decline will be more substantial than simulated here. Conversely, successful policy interventions could reverse trends and lessen the decline.